JP7088239B2 - Semiconductor wafers for epitaxial growth and methods for manufacturing semiconductor epitaxial wafers - Google Patents

Description

The present invention relates to a method for manufacturing a semiconductor wafer for epitaxial growth, a semiconductor wafer for epitaxial growth, and a method for manufacturing a semiconductor epitaxial wafer.

Semiconductor epitaxial wafers in which an epitaxial layer is formed on a semiconductor wafer include various semiconductors such as MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistor), DRAMs (Dynamic Random Access Memory), power transistors, and back-illuminated solid-state imaging devices. It is used as a device substrate for manufacturing devices.

For example, in a back-illuminated solid-state image sensor, by arranging a wiring layer or the like below the sensor unit, light from the outside can be directly taken into the sensor, and clearer images and moving images can be taken even in a dark place. .. Therefore, the back-illuminated solid-state image sensor has been widely used in mobile phones such as digital video cameras and smartphones in recent years.

In recent years, with the increasing miniaturization and higher performance of semiconductor devices, there is a demand for higher quality semiconductor epitaxial wafers used as device substrates in order to improve the quality of device characteristics. In order to further improve the device characteristics, a crystal quality improvement technique by oxygen precipitation heat treatment, a gettering technique for preventing heavy metal contamination during epitaxial growth, and the like have been developed.

The applicant of the present application proposes the following techniques regarding the gettering technique in Patent Document 1. That is, a first step of irradiating a semiconductor wafer with cluster ions to form a modified layer composed of constituent elements of the cluster ions on the surface portion of the semiconductor wafer, and after the first step, the surface of the semiconductor wafer. A second step of heat-treating the semiconductor wafer to restore crystallinity so that the haze level of the semiconductor wafer is 0.20 ppm or less, and after the second step, epitaxial on the modified layer of the semiconductor wafer. It is a method for manufacturing a semiconductor epitaxial wafer having a third step of forming a layer.

The modified layer formed by the technique described in Patent Document 1 becomes a strong gettering site. On the other hand, depending on the cluster ion irradiation conditions, the crystallinity of the outermost surface of the semiconductor wafer before forming the epitaxial layer may be disturbed, and the flatness of the surface of the epitaxial layer after forming the epitaxial layer may be deteriorated. Therefore, by the technique described in Patent Document 1, it is possible to obtain a semiconductor epitaxial wafer having a strong gettering ability and excellent flatness.

By the way, in a semiconductor epitaxial wafer after forming an epitaxial layer, if hydrogen is localized in the modified layer on the surface of the semiconductor wafer as a base substrate, hydrogen is not localized (at least the concentration peak of hydrogen cannot be detected). Compared to wafers, the epitaxial layer has higher overall crystallinity. Further, the hydrogen localized on the surface of the semiconductor wafer, which is the base substrate of the semiconductor epitaxial wafer, maintains high crystallinity even after the semiconductor epitaxial wafer is subjected to the heat treatment corresponding to the device manufacturing process. It is considered that this is because hydrogen passesivates the defects in the epitaxial layer. Therefore, if a semiconductor epitaxial wafer in which hydrogen is localized in the modified layer on the surface of the semiconductor wafer as the base substrate is used in the device manufacturing process, the device quality can be improved.

Therefore, in Patent Document 2, the applicant of the present application has a semiconductor wafer and an epitaxial layer formed on the surface of the semiconductor wafer, and a high-concentration hydrogen peak exists in the modified layer on the surface portion of the semiconductor wafer. We are proposing semiconductor epitaxial wafers.

According to the technique described in Patent Document 2, hydrogen can be localized at a high concentration on the surface portion of the semiconductor wafer, so that the passivation effect by hydrogen can be surely and effective.

Japanese Unexamined Patent Publication No. 2014-99472 Japanese Unexamined Patent Publication No. 2016-51729

Now, in order to localize hydrogen at a high concentration on the surface of the semiconductor wafer while imparting strong gettering ability, carbon and hydrogen should be injected at a high dose in the form of cluster ions on the surface of the semiconductor wafer. good. However, when the semiconductor wafer is irradiated with cluster ions containing carbon and hydrogen as constituent elements at a high dose, an amorphous layer is formed on the surface portion of the semiconductor wafer after irradiation depending on the irradiation conditions. Depending on the amorphous layer to be formed, it is difficult to use such a semiconductor epitaxial wafer for a device process because a large number of epitaxial defects are generated when an epitaxial layer is formed on the layer.

Therefore, the present inventors once recalled that the amorphous layer formed by irradiation with cluster ions was recrystallized. Then, when the heat treatment for crystal recovery (hereinafter referred to as "recovery heat treatment") was performed, the amorphous layer could be recrystallized. Therefore, if the recovery heat treatment is performed, epitaxial defects are generated during the formation of the epitaxial layer. The present inventors thought that it could be suppressed.

However, it has been found that due to such heat treatment during heating, most of the hydrogen localized at a high concentration is diffused on the surface of the semiconductor wafer, and the significance of localizing the hydrogen at a high concentration is diminished. It is considered that this is because the diffusion coefficient of hydrogen in the semiconductor wafer is much larger than the diffusion coefficient of carbon or the like, so that hydrogen diffuses outward during the recovery heat treatment. In this way, even if the amorphous layer is recrystallized by performing the heat treatment, on the other hand, the peak concentration of hydrogen is drastically reduced as compared with that before the heat treatment. Further, since the amorphous layer becomes a gettering site of the semiconductor wafer, recrystallization needs to be appropriately performed from the viewpoint of imparting gettering ability. In this way, the present inventors have newly stated that the cluster ion irradiation region is crystal-recovered for epitaxial growth, hydrogen is maintained at a high concentration on the surface portion of the semiconductor wafer, and strong gettering is imparted. I recognized it as an issue.

Therefore, in view of the above problems, the present invention provides a method for manufacturing a semiconductor wafer for epitaxial growth, which can maintain a high concentration of hydrogen on the surface portion of the semiconductor wafer and can have strong gettering. With the goal. Further, an object of the present invention is to provide a semiconductor wafer for epitaxial growth that can be obtained by this manufacturing method. Another object of the present invention is to provide a method for manufacturing an epitaxial wafer using a semiconductor wafer for epitaxial growth that can be obtained by this manufacturing method.

The present inventors have diligently studied to solve the above-mentioned problems. Since hydrogen is a light element, even if hydrogen is localized on the surface of a semiconductor wafer, hydrogen is likely to diffuse when high-temperature recovery heat treatment is performed. Therefore, the present inventors further studied, and after performing cluster ion irradiation under the condition that an amorphous layer is formed on the surface of the semiconductor wafer, the semiconductor wafer is heated by irradiating the semiconductor wafer with an electromagnetic wave having a predetermined frequency. The idea was to recrystallize the surface side of the semiconductor wafer so as to leave a part of the amorphous layer. By doing so, it was found that a semiconductor wafer for epitaxial growth capable of retaining hydrogen at a high concentration on the surface portion of the semiconductor wafer and having strong gettering can be manufactured, and the present invention is completed. It came to. That is, the gist structure of the present invention is as follows.

(1) The first surface of a semiconductor wafer is irradiated with cluster ions containing carbon and hydrogen as constituent elements to form a modified layer in which the constituent elements of the cluster ions are solid-dissolved on the surface portion of the semiconductor wafer. Process and
After the first step, the semiconductor wafer is irradiated with an electromagnetic wave having a frequency of 300 MHz or more and 3 THz or less, and a heat treatment for recovering crystallinity is performed on the semiconductor wafer.
Have,
In the first step, the cluster ion irradiation is performed under the condition that a part of the modified layer in the thickness direction is an amorphous layer.
In the second step, the surface side is recrystallized to form a single crystal layer by irradiation with the electromagnetic wave, and at least a part of the amorphous layer on the deeper side than the single crystal layer is maintained in an amorphous state. A method for manufacturing a semiconductor wafer for epitaxial growth, which is characterized by the above.

(2) The method for manufacturing a semiconductor wafer for epitaxial growth according to (1) above, wherein the carbon dose amount by the cluster ion irradiation is 1.0 × 10 ¹⁵ atoms / cm ² or more.

(3) The method for manufacturing a semiconductor wafer for epitaxial growth according to (1) or (2) above, wherein the irradiation output of the electromagnetic wave in the second step is 500 W or more and 6 kW or less.

(4) The method for manufacturing a semiconductor wafer for epitaxial growth according to (3) above, wherein the irradiation time of the electromagnetic wave in the second step is 30 seconds or more and 600 seconds or less.

(5) Any of the above (1) to (4), wherein the constituent element of the cluster ion further contains one or more elements selected from the group consisting of oxygen, boron, phosphorus, arsenic and antimony. A method for manufacturing a semiconductor wafer for epitaxial growth according to the above.

(6) The method for manufacturing a semiconductor wafer for epitaxial growth according to any one of (1) to (5) above, wherein the semiconductor wafer is a silicon wafer.

(7) A semiconductor wafer having a modified layer in which carbon and hydrogen are solid-solved on the surface thereof.
The modified layer includes an amorphous layer and a single crystal layer located on the surface side of the semiconductor wafer with respect to the amorphous layer.
A semiconductor wafer for epitaxial growth, wherein the hydrogen is trapped in the amorphous layer.

(8) The semiconductor wafer for epitaxial growth according to (7) above, wherein the peak concentration of the hydrogen concentration profile in the thickness direction of the amorphous layer is 1.0 × 10 ²⁰ atoms / cm ³ or more.

(9) The semiconductor wafer for epitaxial growth according to (7) or (8) above, wherein the amorphous layer has a thickness of 20 nm or more and 50 nm or less.

(10) The semiconductor wafer for epitaxial growth according to any one of (7) to (9) above, wherein the depth of the amorphous layer from the surface of the semiconductor wafer is 20 nm or more and 80 nm or less.

(11) The above-mentioned (7) to (10), wherein one or more elements selected from the group consisting of oxygen, boron, phosphorus, arsenic and antimony are further solid-dissolved in the modified layer. The semiconductor wafer for epitaxial growth according to any one.

(12) The semiconductor wafer for epitaxial growth according to any one of (7) to (11) above, wherein the semiconductor wafer is a silicon wafer.

(13) The semiconductor wafer for epitaxial growth manufactured by the method for manufacturing a semiconductor wafer for epitaxial growth according to any one of (1) to (6) above, or the semiconductor wafer for epitaxial growth according to any one of (7) to (12) above. A method for manufacturing a semiconductor epitaxial wafer, which comprises forming an epitaxial layer on the surface of a semiconductor wafer for epitaxial growth.

According to the present invention, it is possible to provide a method for manufacturing a semiconductor wafer for epitaxial growth, which can maintain a high concentration of hydrogen on the surface portion of the semiconductor wafer and can have strong gettering. , A semiconductor wafer for epitaxial growth that can be obtained by this manufacturing method can be provided. Further, according to the present invention, it is possible to provide a method for manufacturing an epitaxial wafer using a semiconductor wafer for epitaxial growth that can be obtained by this manufacturing method.

It is a typical cross-sectional view explaining the manufacturing method of the semiconductor wafer for epitaxial growth by one Embodiment of this invention. It is a schematic enlarged sectional view explaining the modified layer of the semiconductor wafer for epitaxial growth by one Embodiment of this invention, (A) is the enlarged sectional view after cluster ion irradiation, (B) after electromagnetic wave irradiation. It is an enlarged sectional view of. It is the figure which superposed the TEM cross-sectional photograph of the silicon wafer after irradiation with the cluster ion in an Example, and the graph which shows the concentration profile of carbon and hydrogen of the part corresponding to the TEM cross-section photograph, (A) is a reference. It is a figure of Example 1, (B) is a figure of invention example 1, and is a figure of comparative example 1 of (C). It is a bar graph which shows the peak concentration of hydrogen of Invention Example 1, Comparative Example 1 and Comparative Example 2. It is a bar graph explaining the gettering ability of Invention Example 1 and Comparative Example 2.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Further, in FIGS. 1 and 2, for the sake of simplification of the drawings, the thickness of each configuration is exaggerated and shown differently from the actual thickness ratio.

(Manufacturing method of semiconductor wafer for epitaxial growth)
In the method for manufacturing a semiconductor wafer 10 for epitaxial growth according to an embodiment of the present invention, as shown in FIG. 1, the surface 10A of the semiconductor wafer 10 is irradiated with cluster ions 16 containing carbon and hydrogen as constituent elements to form a semiconductor. After the first step (FIGS. 1A and 1B) for forming the modified layer 18a in which the constituent elements of the cluster ion 16 are solid-dissolved on the surface portion of the wafer 10, and the first step, the frequency is 300 MHz or more. It has a second step of irradiating the semiconductor wafer 10 with an electromagnetic wave W of 3 THz or less and performing a heat treatment for recovering crystallinity on the semiconductor wafer 10. Although the details will be described later, it is considered that the modified layer 18a and the amorphous layer 19a formed in the first step are denatured through the second step. Therefore, in the following, the modified layer and the amorphous layer after the second step are referred to as a modified layer 18b and an amorphous layer 19b, respectively, and when intentionally distinguishing before and after the alteration, the before and after the alteration are identified by reference numerals. ..

In the method for manufacturing a semiconductor wafer 10 according to the present embodiment, in the first step (FIGS. 1A and 1B), cluster ions are formed under the condition that a part of the modified layer 18a in the thickness direction is an amorphous layer 19a. 16 irradiations will be performed. FIG. 2A shows an enlarged schematic cross-sectional view of the modified layer 18a after the first step and before the second step. Further, in the second step (FIGS. 1 (C) and 1 (D)), the surface 10A side of the semiconductor wafer 10 is recrystallized by irradiation with the electromagnetic wave W to form a recrystallized single crystal layer 19c, while forming an amorphous layer. The amorphous layer 19b is formed by maintaining at least a part of the amorphous state of 19a on the deeper side than the recrystallized single crystal layer 19c. FIG. 2B shows an enlarged schematic cross-sectional view of the modified layer 18b after the second step.

FIG. 1D is a schematic cross-sectional view of a semiconductor wafer 10 for epitaxial growth obtained as a result of this manufacturing method, and FIG. 2B is an enlarged schematic cross-sectional view thereof. The semiconductor wafer 10 is suitable for forming an epitaxial layer on the entire surface of the modified layer 18b side. In this case, the formed epitaxial layer becomes a device layer for manufacturing a semiconductor element such as a back-illuminated solid-state image sensor. Hereinafter, details of each process and each configuration will be sequentially described.

<First step>
In the first step of the present embodiment, as described above, the surface 10A of the semiconductor wafer 10 is irradiated with the cluster ions 16 containing carbon and hydrogen as constituent elements, and the surface portion of the semiconductor wafer 10 is configured with the cluster ions 16. The modified layer 18a in which the element is solid-dissolved is formed. Then, in this first step, the cluster ion irradiation is performed under the condition that a part of the modified layer 18a in the thickness direction is an amorphous layer 19a. As shown in the enlarged schematic cross-sectional view of FIG. 2A, the amorphous layer 19a is formed inside the modified layer 18a through the first step.

<< Semiconductor Wafer >>
Examples of the semiconductor wafer 10 prepared in the first step include a bulk single crystal wafer made of silicon and a compound semiconductor (GaAs, GaN, SiC) and having no epitaxial layer on the surface. When manufacturing a back-illuminated solid-state image sensor, a bulk single crystal silicon wafer is generally used. Further, as the semiconductor wafer 10, a single crystal silicon ingot grown by the chokralski method (CZ method) or the floating zone melting method (FZ method) can be sliced with a wire saw or the like. Also, carbon and / or nitrogen may be added to the semiconductor wafer 10 to obtain higher gettering capability. Further, an arbitrary dopant may be added to the semiconductor wafer 10 at a predetermined concentration to form a so-called n + type or p + type, or n− type or p− type substrate.

Further, as the semiconductor wafer 10, an epitaxial semiconductor wafer having a semiconductor epitaxial layer formed on the surface of the bulk semiconductor wafer may be used. For example, it is an epitaxial silicon wafer in which a silicon epitaxial layer is formed on the surface of a bulk single crystal silicon wafer. This silicon epitaxial layer can be formed under general conditions by the CVD method. The thickness of the epitaxial layer is preferably in the range of 0.1 to 20 μm, more preferably in the range of 0.2 to 10 μm.

<< Cluster ion irradiation >>
As used herein, the term "cluster ion" means an ionized cluster in which a plurality of atoms or molecules are aggregated to give a positive charge or a negative charge. A cluster is a mass in which a plurality of atoms or molecules (usually about 2 to 2000) are bonded to each other. In addition, in this specification, "cluster size" means the number of atoms constituting one cluster.

The modified layer 18a is formed by irradiating the semiconductor wafer 10 with the cluster ions 16. The details of the formation process of the modified layer 18a will be specifically described with reference to FIG. 2A, taking as an example a case where the irradiation target is a silicon wafer (that is, a case where a silicon wafer is used as the semiconductor wafer 10). ..

When a silicon wafer, which is a type of semiconductor wafer, is irradiated with cluster ions containing carbon and hydrogen as constituent elements, the cluster ion 16 instantaneously has a high temperature of about 1350 to 1400 ° C. with its energy when the silicon wafer is irradiated. It becomes a state and the silicon melts. After that, the silicon is rapidly cooled inside the silicon wafer, and carbon and hydrogen are locally and highly concentrated in the vicinity of the surface in the silicon wafer.

As used herein, the term "modified layer" means a layer in which the constituent elements of the irradiated cluster ions are solid-solved at the interstitial position or the substitution position of the crystal on the surface of the semiconductor wafer. The carbon concentration profile in the depth direction of a silicon wafer by secondary ion mass spectrometry (SIMS) depends on the acceleration voltage and cluster size of cluster ions, but is sharper than that of monomer ions. The thickness of the locally present region (that is, the modified layer) of the irradiated carbon is approximately 500 nm or less (for example, about 50 to 400 nm). In addition, the "concentration profile in the thickness direction" in the present specification means the concentration distribution in the depth direction measured by SIMS. Further, in the present specification, the “thickness of the modified layer” t ₀ refers to a thickness range in which the carbon concentration exceeds 1.0 × 10 ¹⁷ atoms / cm ³ . The element irradiated in the form of cluster ions diffuses to some extent by the recovery heat treatment in the second step, but the thickness of the modified layer does not change significantly before and after the recovery heat treatment. When the constituent elements of the cluster ion 16 contain elements that contribute to gettering such as carbon, the modified layer 18a also functions as a gettering site.

In this way, the irradiation of the cluster ions 16 forms a modified layer 18a in which the constituent elements of the cluster ions 16 including carbon and hydrogen are solid-solved on the surface portion of the semiconductor wafer 10. Here, in the present embodiment, the cluster ion irradiation is performed under the condition that the amorphous layer 19a is intentionally formed. Since the irradiation damage given to the surface layer portion of the semiconductor wafer 10 is large depending on the dose amount and acceleration energy of the cluster ion 16, amorphous is formed in the modified layer 18a on the deeper side than the predetermined depth from the surface 10A of the semiconductor wafer 10. It begins to form. The surface portion of the semiconductor wafer 10 is heated by the influence of irradiation, and the heating recovers the damage introduced to the surface portion by the irradiation of the cluster ions 16 (self-annealing effect). The thickness of the amorphous layer 19a is determined by the irradiation conditions of the cluster ions 16 and the self-annealing effect described above, and a non-amorphous region may be formed in the outermost layer portion of the semiconductor wafer 10.

The depth of the surface of the formed amorphous layer 19a may vary depending on the position in the lateral direction, but in the present specification, the "depth of the amorphous layer 19a from the surface 10A of the semiconductor wafer 10" D ₁ is amorphous. The cross section of the layer is observed with a transmission electron microscope (TEM) and is defined by the average depth of the surface in the obtained TEM image. The "average depth" is defined as a depth between the shallowest position and the deepest position of the boundary line between the amorphous layer 19a and the crystal region. Further, the "thickness of the amorphous layer 19a" t ₁ is also defined by the average thickness of the amorphous layer 19a in the TEM image, that is, the difference in the average depth of the amorphous layer 19a from the semiconductor wafer surface 10A at the front and back interfaces. The magnification of the TEM image may be such that the amorphous layer can be clearly observed, and is set to 600,000 times in the example shown in FIG. The depth D ₂ from the surface 10A of the amorphous layer 19b and the thickness t ₂ of the amorphous layer 19b after irradiation with electromagnetic waves, which will be described later, are also defined in the same manner as the depth D ₁ and the thickness t ₁ , respectively.

The thickness t ₁ of the amorphous layer 19a formed by the present embodiment can be 30 nm or more and 150 nm or less, and is smaller than the thickness t ₀ of the modified layer 18a. It is more preferable that the thickness t ₁ is 50 nm or more and 100 nm or less. Further, the depth D ₁ from the surface 10A of the amorphous layer 19a is usually 10 nm or less, and when the crystal is recovered, D ₁ is 0.1 nm or more.

Whether or not the amorphous layer 19a is formed in the modified layer 18a, and the depth D ₁ of the surface 10A of the amorphous layer 19a when formed, are the dose amount of cluster ions, the cluster size, and the acceleration of cluster ions. It is controlled by cluster ion irradiation conditions including voltage, beam current value, substrate temperature at the time of irradiation, etc., and among them, it largely depends on the dose amount and cluster size.

The irradiation conditions for forming the amorphous layer 19a may be appropriately selected from the above irradiation conditions, and in order to form the amorphous layer 19a more reliably, the amount of carbon dose by cluster ion irradiation is 1.0 × 10 ¹⁵ It is preferably atoms / cm ² or more. Further, the carbon dose amount is more preferably 1.5 × 10 ¹⁵ atoms / cm ² or more, and further preferably 2.0 × 10 ¹⁵ atoms / cm ² or more. The dose amount of cluster ions can be adjusted by controlling the irradiation time of cluster ions.

Further, by irradiating the cluster ions with the substrate temperature kept lower than room temperature (25 ° C.), the amorphous layer 19a can be easily formed. When the substrate temperature at the time of cluster ion irradiation is low, the above-mentioned self-annealing effect is hindered and the introduced damage is not sufficiently recovered. Therefore, the amorphous layer tends to remain on the surface of the semiconductor wafer 10. Of course, in the present embodiment, since the amorphous layer 19a may be formed, the wafer temperature at the time of irradiation may be room temperature or lower than 25 ° C., for example, 0 ° C. or lower, while the temperature may be higher than room temperature. It doesn't matter.

Further, the amount of carbon dose that can surely form the amorphous layer 19a also differs depending on the cluster ion species and the cluster size. Although it depends on the cluster ion irradiation conditions, when C ₃ H ₅ is used as the cluster ions, the amorphous layer 19a is formed more reliably by setting the carbon dose amount to 1.7 × 10 ¹⁵ atoms / cm ² or more. be able to. Further, when C ₃ H ₃ is used as the cluster ion, the amorphous layer 19a can be formed more reliably by setting the carbon dose amount to 2.2 × 10 ¹⁵ atoms / cm ² or more. In addition, when CH ₃ O is used as the cluster ion, the amorphous layer 19a can be formed more reliably by setting the carbon dose amount to 1.0 × 10 ¹⁵ atoms / cm ² or more.

It is preferable that the constituent elements of the cluster ion 16 further contain one or more elements selected from the group consisting of oxygen, boron, phosphorus, arsenic and antimony, in addition to carbon and hydrogen. Oxygen atoms have a larger mass number and a larger atomic radius than carbon atoms. Therefore, since the constituent elements of the cluster ion 16 contain oxygen, irradiation damage can be increased even if the amount of carbon dose is small, and the amorphous layer 19a can be formed more reliably. Further, it is also preferable that the cluster ion 16 contains one or more elements selected from the group consisting of the carrier dopant elements boron, phosphorus, arsenic and antimony as constituent elements. This is because the types of metals that can be efficiently gettered differ depending on the type of element that dissolves in solid solution, and therefore, by dissolving a plurality of elements in solid solution, a wider range of metal contamination can be dealt with. For example, in the case of carbon, nickel (Ni) can be efficiently gettered, and in the case of boron, copper (Cu) and iron (Fe) can be efficiently gettered. Further, when the constituent element of the cluster ion 16 contains the dopant element, the injection damage generated in the modified layer 18a is also increased.

The compound source (ion source) to be ionized to generate the cluster ion 16 is not particularly limited, but ethane, methane, carbon dioxide (CO ₂ ) and the like can be used as the carbon source compound capable of ionization. .. For example, if cyclohexane (C ₆ H ₁₂ ) is used as a material gas, cluster ions composed of carbon and hydrogen can be generated. As the carbon source compound, it is particularly preferable to use cluster C _n H _m (3 ≦ n ≦ 16, 3 ≦ m ≦ 10) produced from pyrene (C ₁₆ H ₁₀ ), dibenzyl (C ₁₄ H ₁₄ ), or the like. This is because it is easy to control a small-sized cluster ion beam.

Further, as a boron source compound capable of ionization, diborane, decabolane (B ₁₀ H ₁₄ ) and the like can be used. For example, when a gas obtained by mixing dibenzyl and decaborane is used as a material gas, a hydrogen compound cluster in which carbon, boron and hydrogen are aggregated can be generated.

In addition, as an ion source of cluster ions containing carbon, hydrogen and oxygen as constituent elements, diethyl ether (C ₄ H ₁₀ O), ethanol (C ₂ H ₆ O), diethyl ketone (C ₅ H ₁₀ O), etc. Can also be used. As an ion source containing three elements of carbon, hydrogen and oxygen, in particular, clusters CnHmOl ( _l , _m , _n are independent of each other and 1 ≦ n ≦ 16) generated from diethyl ether, ethanol, etc. , 1 ≦ m ≦ 16, 1 ≦ l ≦ 16) is preferable.

<Second step>
After the first step, as the second step, the semiconductor wafer 10 is irradiated with an electromagnetic wave W having a frequency of 300 MHz or more and 3 THz or less, and a heat treatment for recovering crystallinity is performed on the semiconductor wafer 10 (FIG. 1 (C), (D)). The modified phase 18a formed in the first step becomes a modified layer 18b through the second step, and an enlarged schematic diagram thereof is shown in FIG. 2 (B). Hereinafter, the details of this step will be described.

In this second step, the surface 10A side of the modified layer 18a is recrystallized to form the single crystal layer 19c. On the other hand, the above-mentioned electromagnetic wave irradiation is performed so as to maintain at least a part of the amorphous state on the deep side of the single crystal layer 19c of the amorphous layer 19a. The amorphous layer 19a formed by irradiation with the cluster ions 16 is reduced in thickness after irradiation with electromagnetic waves to become the amorphous layer 19b. At this time, the amorphous layer 19b is altered from the amorphous layer 19a to capture hydrogen. As shown in FIG. 2B, the deep side of the amorphous layer 19a may be recrystallized by the electromagnetic wave irradiation, but the deep side may not be recrystallized.

Here, an electromagnetic wave having a frequency of 300 MHz or more and 3 THz or less is called a “microwave” in a broad sense. The heating of the semiconductor wafer 10 by irradiation with electromagnetic waves having a frequency of 300 MHz or more and 3 THz or less is called "microwave heating" or "microwave annealing". Hereinafter, in the present specification, heating of the semiconductor wafer 10 by irradiation with electromagnetic waves having a frequency of 300 MHz or more and 3 THz or less is simply referred to as “microwave heating”.

In the second step, the modified layer 18b is oscillated and locally heated by microwave heating to form the above-mentioned amorphous layer 19b and the single crystal layer 19c. In order to recrystallize a part of the amorphous layer 19a and leave a part in the amorphous state, the irradiation output of the microwave to be irradiated is preferably 500 W or more and 6 kW or less, and 2 kW or more and 5 kW or less. Is more preferable. Within these output ranges, the amorphous layer 19b and the single crystal layer 19c can be obtained by recrystallizing the surface 10A side while partially retaining the amorphous state of the amorphous layer 19a. Then, hydrogen can be sufficiently retained in the amorphous layer 19b. On the other hand, if the output becomes excessive, the amorphous layer 19a is completely recrystallized, and hydrogen is also diffused. Further, if the output is too small, the amorphous layer 19a will not be recrystallized. The "output" of the microwave referred to in the present specification refers to the device output as a microwave generator of the microwave heating device. Further, as the microwave heating device used in this step, a commercially available magnetron type microwave oscillator or the like can be used.

Further, the irradiation time of the electromagnetic wave is preferably 30 seconds or more and 600 seconds or less, and more preferably 60 seconds or more and 400 seconds or less. Within these irradiation times, the amorphous layer 19b can be obtained by recrystallizing the surface 10A side while leaving a part of the amorphous state of the amorphous layer 19a more reliably. If the irradiation time is insufficient, the recrystallization of the wafer surface becomes insufficient, and on the other hand, even if the irradiation time is long, the recovery effect is saturated and hydrogen is diffused.

The frequency of the electromagnetic wave (microwave in a broad sense) to be irradiated can be from a millimeter wave to an infrared region, and for example, it is also preferable to set it as a "microwave in a narrow sense" of 300 MHz or more and 300 GHz or less. Further, it is particularly preferable that the frequency of the microwave to be irradiated is within the range of 2450 MHz ± 50 MHz, which is the frequency of the magnetron type microwave oscillator, or within the range of 2450 MHz ± 30 MHz.

Here, the details will be described later in Examples, but the present inventors measured the modified layer 18b formed by the production method according to the present embodiment by SIMS while acquiring a TEM image, and measured the modified layer 18b in the thickness direction. When the concentration profiles of carbon and hydrogen were obtained and the amorphous part and the recrystallized part were compared (see FIG. 3B), the following facts were found.
(I) Carbon and hydrogen concentration profiles in the thickness direction intersect in the vicinity of both the surface 10A side and the deep side of the semiconductor wafer 10 of the amorphous layer 19b.
(Ii) In the thickness direction, hydrogen is present in a high concentration in the amorphous layer 19b.
(Iii) A steep decrease in the density of the profile is observed near both interfaces of the amorphous layer 19b.
Such crossing of concentration profiles and localization of hydrogen in the amorphous layer 19b were realized for the first time by the production method according to the present embodiment. Then, it became clear that the amorphous layer 19b formed according to the present embodiment captures hydrogen.

By forming such an amorphous layer 19b, the peak concentration of the hydrogen concentration profile in the thickness direction of the modified layer 18b can be 1.0 × 10 ²⁰ atoms / cm ³ or more, and 2.0 × 10 ²⁰ atoms. It can be / cm ³ or more, or 3.0 × 10 ²⁰ atoms / cm ³ or more. The larger the peak concentration of hydrogen, the more the passivation effect of hydrogen can be expected.

The thickness t ₂ of the amorphous layer 19b formed by the present embodiment can be 20 nm or more and 50 nm or less. The thickness t _{2 is} smaller than the thickness t ₁ of the amorphous layer 19a before microwave heating. Further, the depth D ₂ from the surface 10A of the amorphous layer 19b can be 20 nm or more and 80 nm or less, and the depth D ₂ is larger than D ₁ . The depth D ₂ corresponds to the thickness of the recrystallized single crystal layer 19c.

As described above, carbon can be diffused by microwave heating, but the thickness t ₀ of the modified layer 18a before microwave heating does not change significantly even after microwave heating. Therefore, in FIG. 2, the thickness of the modified layer 18b is schematically shown as being the same as the thickness t ₀ of the modified layer 18a.

<Semiconductor wafer>
The semiconductor wafer 10 thus manufactured can retain hydrogen at a high concentration on the surface portion of the semiconductor wafer by the amorphous layer 19b formed by microwave heating. Therefore, the passivation effect of hydrogen can be expected. Further, an amorphous layer 19b is formed in the modified layer 18b, and the amorphous layer 19b also functions even at a gettering site. Further, since the recrystallized single crystal layer 19c having a sufficient thickness can be formed by microwave heating, even if an epitaxial layer is formed on the single crystal layer 19c, the generation of epitaxial defects can be suppressed.

As described above, according to the present embodiment, there is provided a method for manufacturing a semiconductor wafer for epitaxial growth, which can maintain a high concentration of hydrogen on the surface portion of the semiconductor wafer and can have strong gettering. be able to.

A semiconductor epitaxial wafer can be manufactured by forming an epitaxial layer on the modified layer 18b of the semiconductor wafer 10 for epitaxial growth. Examples of the epitaxial layer include a silicon epitaxial layer, which can be formed under general conditions. In this case, for example, hydrogen is used as a carrier gas, and a source gas such as dichlorosilane or trichlorosilane is introduced into the chamber, and the growth temperature varies depending on the source gas used, but CVD is performed at a temperature in the range of approximately 1000 to 1200 ° C. It can be epitaxially grown on a semiconductor wafer by the method. The thickness of the epitaxial layer is preferably in the range of 1 to 15 μm. If it is less than 1 μm, the resistivity of the epitaxial layer may change due to the outward diffusion of the dopant from the semiconductor wafer, and if it exceeds 15 μm, the spectral sensitivity characteristics of the solid-state image sensor may be affected. Because there is.

Hereinafter, the irradiation mode of cluster ions in this embodiment will be described more specifically.

There are various types of cluster ions depending on the binding mode, and cluster ions can be generated by a known method as described in the following documents, for example. As a method for generating a gas cluster beam, (1) Japanese Patent Application Laid-Open No. 9-41138, (2) Japanese Patent Application Laid-Open No. 4-354865, as a method for generating an ion beam, (1) Charged particle beam engineering: Junzo Ishikawa: ISBN978 -4-339-00734-3: Corona Publishing Co., Ltd., (2) Electron / Ion Beam Engineering: Institute of Electrical Engineers of Japan: ISBN4-88686-217-9: Ohmsha Publishing Co., Ltd., (3) Cluster Ion Beam Basics and Applications: ISBN4-526-05765 -7: Nikkan Kogyo Shimbun. In general, a Nielsen-type ion source or a Kaufmann-type ion source is used to generate positively charged cluster ions, and a large-current negative ion source using the volume generation method is used to generate negatively charged cluster ions. Be done.

The cluster size can be appropriately set from 2 to 100, preferably 60 or less, and more preferably 50 or less. The cluster size can be adjusted by adjusting the gas pressure of the gas ejected from the nozzle, the pressure of the vacuum vessel, the voltage applied to the filament during ionization, and the like. The cluster size can be obtained by obtaining the cluster number distribution by mass spectrometry using a quadrupole high-frequency electric field or time-of-flight mass spectrometry, and taking the average value of the number of clusters.

Even after the epitaxial layer is formed, the beam current value of the cluster ion 16 is preferably 50 μA or more in order to further increase the peak concentration of hydrogen on the surface portion of the semiconductor wafer 10. When the cluster ion 16 containing hydrogen is irradiated under the above current value conditions, the hydrogen contained in the constituent elements of the cluster ion 16 is more reliably dissolved in the surface portion of the semiconductor wafer 10 in excess of the equilibrium concentration. In order to obtain this effect more reliably, the beam current value is more preferably 100 μA or more, and further preferably 300 μA or more. The beam current value of the cluster ion 16 can be adjusted, for example, by changing the decomposition conditions of the raw material gas in the ion source.

On the other hand, if the beam current value becomes excessive, epitaxial defects may be excessively generated in the epitaxial layer 20, so that the beam current value is preferably 5000 μA or less.

In addition, the acceleration voltage of the cluster ion affects the peak position of the concentration profile in the depth direction of the constituent elements of the cluster ion together with the cluster size. In the present embodiment, the acceleration voltage of the cluster ion can be more than 0 keV / Cluster and less than 200 keV / Cluster, preferably 100 keV / Cluster or less, and more preferably 80 keV / Cluster or less.

In the modified layer 18a after the first step, it is preferable to perform cluster ion irradiation so that the peak of the carbon concentration profile exists within the range from the surface 10A of the semiconductor wafer 10 to the depth of 150 nm in the depth direction. .. Further, in the modified layer 18a, the peak concentration of the carbon concentration profile is preferably 1.0 × 10 ¹⁹ atoms / cm ³ or more, and cluster ion irradiation is performed so as to be 1.0 × 10 ²⁰ atoms / cm ³ or more. It is preferable to do.

Further, it is preferable to perform cluster ion irradiation so that the half width (FWHM) of the peak of the carbon concentration profile in the depth direction of the semiconductor wafer 10 in the modified layer 18a is 100 nm or less. The modified layer 18a having such a half-value width is a region where carbon is dissolved locally at the interstitial position or the substitution position of the crystal on the surface of the semiconductor wafer, and can act as a strong gettering site. can. Further, from the viewpoint of obtaining a high gettering ability, the half width is more preferably 85 nm or less, and the lower limit can be set to 10 nm. Although carbon diffuses to some extent through the second step, the half width (FWHM) of the peak of the carbon concentration profile does not change significantly, and the half width (FWHM) can be 100 nm or less, more preferably 85 nm or less. Preferably, the lower limit can be set to 10 nm.

(Semiconductor wafer for epitaxial growth)
Next, the semiconductor wafer 10 for epitaxial growth obtained according to the embodiment of the above manufacturing method will be described. In principle, the same reference numbers are assigned to the same components as those in the above-described manufacturing method embodiment, and duplicate explanations will be omitted.

As shown in FIGS. 1 (D) and 2 (B), the semiconductor wafer 10 for epitaxial growth according to one embodiment of the present invention has a modified layer 18b in which carbon and hydrogen are solid-solved on the surface thereof. The modified layer 18b includes an amorphous layer 19b and a single crystal layer 19c located on the surface 10A side of the semiconductor wafer 10 with respect to the amorphous layer 19b, and hydrogen is captured in the amorphous layer 19b. The "recrystallized single crystal layer 19c" in the embodiment of the above-mentioned production method corresponds to the "single crystal layer 19c" of the present embodiment.

Here, in the present specification, "hydrogen is captured in the amorphous layer 19b" means that "hydrogen is captured in the amorphous layer 19b" in the vicinity of both interfaces on the surface 10A side and the deep side of the semiconductor wafer 10 of the amorphous layer 19b (specifically, centering on the interface). In the thickness direction (within ± 5 nm), it means that the carbon and hydrogen concentration profiles in the thickness direction intersect. In particular, in the thickness direction, the amorphous layer 19b has a high concentration region having a thickness of 20 nm or more and a hydrogen concentration of 5.0 × 10 ¹⁹ atoms / cm ³ or more as compared with other regions of the modified layer 18b. Means. Further, a steep concentration change of the hydrogen concentration profile (specifically, per 1 nm in the thickness direction) in the vicinity of both interfaces of the amorphous layer 19b (specifically, within the range of ± 5 nm in the thickness direction around the interface). 0 × 10 ¹⁹ atoms / cm ³ or more increase or decrease) is observed.

In the semiconductor wafer 10, hydrogen is captured in a high concentration in the amorphous layer 19b. Further, since the amorphous layer 19b is formed in the modified layer 18b, it functions even if it is a strong gettering site. Further, since the single crystal layer 19c is formed on the amorphous layer 19b, the epitaxial layer can be formed on the single crystal layer 19c.

As described above, the semiconductor wafer 10 for epitaxial growth according to the present embodiment can hold hydrogen at a high concentration on the surface portion of the semiconductor wafer and can have strong gettering, and thus can be subjected to epitaxial growth. Suitable.

Further, in order to make the passion effect by hydrogen more reliable, the peak concentration of the hydrogen concentration profile in the thickness direction of the amorphous layer 19b is preferably 1.0 × 10 ²⁰ atoms / cm ³ or more, preferably 2.0. It is more preferably x10 ^{20 atoms / cm 3 or more, and particularly preferably 3.0 × 10 20 atoms / cm 3 or more} .

Further, in order to secure the thickness of the single crystal layer 19c, it is preferable that the depth D ₂ of the amorphous layer 19b from the surface 10A of the semiconductor wafer 10 is 20 nm or more and 80 nm or less. Further, since it has a strong gettering ability, it is preferable that the thickness t ₂ of the amorphous layer 19b is 20 nm or more and 50 nm or less.

Further, in order to have excellent gettering ability, one or more elements selected from the group consisting of oxygen, boron, phosphorus, arsenic and antimony may be further dissolved in the modified layer 18b. preferable. Since it has a gettering ability, the half width (FWHM) of the peak of the carbon concentration profile in the thickness direction of the modified layer 18b can be 100 nm or less, more preferably 85 nm or less, and the lower limit is 10 nm. Can be set.

Further, a silicon wafer can be used as the semiconductor wafer 10.

(Manufacturing method of semiconductor epitaxial wafer)
In the method for manufacturing a solid-state image sensor according to the embodiment of the present invention, an epitaxial layer is formed on the surface 10A of the semiconductor wafer 10 for epitaxial growth manufactured by the above manufacturing method or on the surface 10A of the semiconductor wafer 10 for epitaxial growth. do. The semiconductor epitaxial wafer obtained by this manufacturing method can hold hydrogen at a high concentration on the surface portion of the semiconductor wafer and can have strong gettering.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples.

<Reference example 1>
An n-type silicon wafer (diameter: 300 mm, thickness: 775 μm, dopant type: phosphorus, resistivity: 10 Ω · cm) obtained from a CZ single crystal was prepared. Next, using a cluster ion generator (manufactured by Nissin Ion Kikai Co., Ltd., model number: CLARIS), cluster ions of C ₃ H ₅ obtained by cluster ionizing cyclohexane (C ₆ H ₁₂ ) were subjected to an acceleration voltage of 80 keV / Cruster (hydrogen 1). The acceleration voltage per atom is 1.95 keV / atom, the acceleration voltage per carbon atom is 23.4 keV / atom, the hydrogen range is 40 nm, and the carbon range is 80 nm). The surface of the above was irradiated to obtain a silicon wafer according to Reference Example 1. The dose amount when irradiated with cluster ions was 1.0 × 10 ¹⁵ cluster / cm ² . When converted to the number of hydrogen atoms, it is 5.0 × 10 ¹⁵ atoms / cm ² , and when converted to the number of carbon atoms, it is 3.0 × 10 ¹⁵ atoms / cm ² . The beam current value of the cluster ions was set to 800 μA.

<Invention Example 1>
The silicon wafer was irradiated with cluster ions under the same conditions as in Reference Example 1. Next, a silicon wafer was microwave-heated using a microwave heating device (DSG) manufactured by Hitachi Kokusai Electric Inc. to obtain a silicon wafer according to Invention Example 1. The conditions for irradiating electromagnetic waves when heating with microwaves were as follows.
Microwave output: 4kW
Estimated wafer temperature: 600 ° C
Microwave irradiation time: 300 seconds Frequency: 2.45 GHz

<Comparative Example 1>
The silicon wafer according to Comparative Example 1 was subjected to cluster ion irradiation and microwave heating under the same conditions as in the first invention except that the microwave heating condition in the first invention was changed from 4 kW to 8 kW. Obtained a wafer.

<Comparative Example 2>
The silicon wafer was irradiated with cluster ions under the same conditions as in Reference Example 1. Next, the silicon wafer was heated to recover the crystals using a resistance heating type heating furnace, and the silicon wafer according to Comparative Example 2 was obtained. The resistance heating conditions were as follows.
Heating temperature: 850 ° C
Heating time: 300 seconds

<Evaluation 1: Observation by TEM cross-sectional photograph>
For each of the silicon wafers according to Reference Example 1, Invention Example 1 and Comparative Examples 1 and 2, the cross section around the modified layer after irradiation with cluster ions was observed with a TEM (Transmission Electron Microscope). The TEM cross-sectional view of Reference Example 1 is shown in FIG. 3 (A), the TEM cross-sectional view of Invention Example 1 is shown in FIG. 3 (B), and the TEM cross-sectional view of Comparative Example 1 is shown in FIG. 3 (C). In Comparative Example 2, all the amorphous layers were recrystallized.

The depth of 0 nm in FIGS. 3A to 3C corresponds to the surface of each silicon wafer. The region in which the white portion from 5 nm to 85 nm in the depth direction in the TEM cross-sectional photograph of FIG. 3 (A) and the white portion from 35 nm to 65 nm in the depth direction in the TEM cross-sectional photograph of FIG. 3 (B) are amorphous. Is. Further, in the TEM cross-sectional photograph of FIG. 3C, the portion that appears white from 0 nm to 55 nm in the depth direction is a recrystallized region, and the portion that appears linearly black from 55 nm to 60 nm in the depth direction is a crystal defect region. Is. In addition, in FIGS. 3A to 3C, the concentration profile by SIMS below is superposed on the TEM cross-sectional view. Comparing FIG. 3 (A) with FIGS. 3 (B) and 3 (C), it can be seen that the crystallinity was partially or wholly restored by microwave heating, and some alteration occurred. A non-amorphous region is formed in the outermost layer from 0 nm to 5 nm in the depth direction of FIG. 3 (A).

<Evaluation 2: Concentration profile evaluation of silicon wafer by quadrupole SIMS>
For each of the silicon wafers according to Reference Example 1, Invention Example 1 and Comparative Examples 1 and 2, quadrupole SIMS (resolution in the depth direction: 2 nm, carbon detection lower limit: 1.0 × 10 ¹⁷ atoms / cm ³ , Hydrogen detection lower limit: 1.0 × 10 ¹⁸ atoms / cm ³ ) was used to measure the respective concentration profiles of carbon and hydrogen in the depth direction. The concentration profile of Reference Example 1 is shown in FIG. 3 (A), the concentration profile of Invention Example 1 is shown in FIG. 3 (B), and the concentration profile of Comparative Example 1 is shown in FIG. 3 (C). Further, FIG. 4 shows a bar graph comparing the peak concentrations of hydrogen in Invention Example 1 and Comparative Examples 1 and 2. Although FIGS. 3A to 3C do not show a concentration profile having a depth of more than 200 nm, the thickness of the modified layer in Reference Example 1, Invention Example 1 and Comparative Example 1 was 300 nm. ..

From FIGS. 3 (A) to 3 (C) and FIG. 4, it is confirmed that the peak concentration of hydrogen is reduced through microwave heating. From FIGS. 3B and 3C, it can be confirmed that hydrogen remains on the outermost surface of the silicon wafer and in the carbon injection range even after microwave heating. Furthermore, the following facts could be confirmed from FIG. 3 (B).
(I) The carbon concentration profile and the hydrogen concentration profile intersect in the vicinity of both the interface between the surface side and the deep side of the silicon wafer of the amorphous layer (at depth positions of 35 nm and 65 nm, respectively).
(Ii) Hydrogen is present in a high concentration of 2.0 × 10 ²⁰ atoms / cm ³ or more in an amorphous layer having a thickness of about 30 nm.
(Iii) A steep density change in the profile is observed near both interfaces of the amorphous layer (particularly at depth positions of 30 to 40 nm and 65 nm to 70 nm, respectively).

Comparing Comparative Examples 1 and 2, it can also be confirmed that the maximum value of the hydrogen concentration is reduced by performing resistance heating. It is considered that this is due to the difference between the local heating of the silicon wafer by microwave heating and the heating of the entire silicon wafer by resistance heating.

<Evaluation 3: Gettering ability evaluation>
The surfaces of Invention Example 1 and Comparative Example 2 were forcibly contaminated with a Ni contaminated solution (1.0 × 10 ¹³ atoms / cm ² ) by a spin coating contamination method, and then 10 at 700 ° C. in a nitrogen atmosphere. It was heat treated for a minute. After that, SIMS measurement was performed for each wafer, and the nickel (Ni) concentration profile in the wafer thickness direction was measured. From the Ni concentration profile, the capture behavior of Ni can be confirmed, and the peak concentration of Ni is an index of gettering ability. The larger the peak concentration of Ni, the larger the amount of Ni captured. The peak concentration of Ni in Invention Example 1 and Comparative Example 2 is shown in the bar graph of FIG. It can be confirmed that Invention Example 1 is gettering more Ni than Comparative Example 2. This is because the amorphous layer is formed in the first aspect of the invention, and the gettering effect of the amorphous layer contributes to this.

As described above, in Invention Example 1 according to the conditions of the present invention, it was confirmed that hydrogen can be maintained at a high concentration on the surface portion of the silicon wafer and that strong gettering can be imparted. Furthermore, it was confirmed that a single crystal layer having a sufficient thickness could be formed in Invention Example 1.

According to the present invention, it is possible to provide a method for manufacturing a semiconductor wafer for epitaxial growth, which can maintain a high concentration of hydrogen on the surface portion of the semiconductor wafer and can have strong gettering. , A semiconductor wafer for epitaxial growth that can be obtained by this manufacturing method can be provided. Further, according to the present invention, it is possible to provide a method for manufacturing an epitaxial wafer using a semiconductor wafer for epitaxial growth that can be obtained by this manufacturing method.

10 Semiconductor wafer 10A Surface of semiconductor wafer 16 Cluster ions 18a, 18b Modified layer 19a, 19b Amorphous layer 19c Single crystal layer W Electromagnetic wave

Claims (4)

A semiconductor wafer having a modified layer in which carbon and hydrogen are solid-dissolved on the surface.
The modified layer includes an amorphous layer and a single crystal layer located on the surface side of the semiconductor wafer with respect to the amorphous layer.
The hydrogen is captured in the amorphous layer,
The peak concentration of the hydrogen concentration profile in the thickness direction of the amorphous layer is 1.0 × 10 ²⁰ atoms / cm ³ or more.
The thickness of the amorphous layer is 20 nm or more and 50 nm or less, and the depth of the amorphous layer from the surface of the semiconductor wafer is 20 nm or more and 80 nm or less.
For epitaxial growth, the carbon concentration profile and the hydrogen concentration profile intersect in the vicinity of both interfaces of the amorphous layer on the surface side and the deep side of the semiconductor wafer within a range of ± 5 nm in the thickness direction centering on the interface. Semiconductor wafers. The epitaxial growth according to any one of claims 1 , wherein one or more elements selected from the group consisting of oxygen, boron, phosphorus, arsenic and antimony are further solid-dissolved in the modified layer. Semiconductor wafer for. The semiconductor wafer for epitaxial growth according to claim 1 or 2, wherein the semiconductor wafer is a silicon wafer. A method for manufacturing a semiconductor epitaxial wafer, which comprises forming an epitaxial layer on the surface of the semiconductor wafer for epitaxial growth according to any one of claims 1 to 3.

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