JPH026222B2 - - Google Patents

Description

[Detailed Description of the Invention] (a) Technical Field of the Invention The present invention relates to a method for manufacturing a semiconductor device, and in particular to a method for manufacturing a semiconductor device.
The present invention relates to a method for manufacturing a semiconductor device that is less affected by wires.

(b) Prior Art and Problems As semiconductor devices become more densely packed into LSIs and VLSIs, and as elements become smaller, the effects of naturally occurring α rays become increasingly severe. In other words, when α rays are received, pairs of electrons and holes are generated within the semiconductor device and these diffuse into the semiconductor device, causing damage to the semiconductor device, such as rewriting information written in the semiconductor memory device. This may cause malfunction.

In order to prevent the effects of alpha rays, it goes without saying that it is necessary to prevent alpha rays from entering semiconductor devices as much as possible, but since it is impossible to completely eliminate alpha rays from entering semiconductor devices, When α rays enter, it is necessary to reduce the number of pairs of electrons and holes that are generated as much as possible, and to quickly annihilate the generated electrons and holes so that they do not reach the device.

For the former purpose, the width of the defect-free layer may be reduced, and for the latter purpose, internal defects may be formed in the semiconductor support substrate.

For this purpose, in the past, a predetermined amount of oxygen (O ₂ ) was contained in the semiconductor support substrate in advance, and heat treatment was performed to precipitate the oxygen (O ₂ ), thereby focusing on SiOx defect nuclei. An internal defect is generated, a defect-free layer is formed on the surface of the semiconductor supporting substrate by utilizing the gettering effect of the internal defect, and a desired silicon single crystal layer is grown on the layer by an epitaxial growth method. A predetermined semiconductor element was formed on the Al growth layer.

In the conventional semiconductor device manufacturing method described above, it is difficult to strictly control the thickness of the defect-free layer formed on the surface of the semiconductor support substrate. An unnecessary defect-free layer remains between the bottom surface of the element that spreads within the defect-free layer,
Therefore, it cannot be said that the adverse effects of alpha rays have been sufficiently eliminated.

(c) Object of the Invention An object of the present invention is to solve the above-mentioned problems and provide a method for manufacturing a semiconductor device that can form a defect-free layer with high precision in thickness.

(d) Structure of the Invention The present invention is characterized by a step of implanting oxygen or carbon into the surface of a silicon support substrate to a predetermined depth by ion implantation, and a step of implanting oxygen or carbon into the silicon support substrate at 650 [°C].
a step of forming a defect nucleus with the implantable oxygen or carbon as a nucleus by performing heat treatment at a temperature of 1070 [°C] to 800 [°C]; and a heat treatment of the silicon support substrate at a temperature of 1070 [°C] to 1250 [°C]. to form a defect-free layer on the surface of the silicon support substrate, and then grow a desired silicon single crystal layer on the defect-free layer by an epitaxial growth method, and add a desired silicon single crystal layer to the silicon single crystal layer. The purpose is to form an element.

(e) Examples of the invention An embodiment of the present invention will be described below with reference to the drawings.

1 to 5 are sectional views of essential parts showing an embodiment of the present invention in the order of manufacturing steps.

In Figure 1, 1 is a supporting substrate (hereinafter simply referred to as Si substrate) made of silicon (Si), which is usually
It is manufactured by controlling the concentration of interstitial oxygen (O ₂ ) contained inside using the CZ method. For example, oxygen ions (O ^- ) are generated on the surface of this Si substrate 1 at an acceleration voltage of about 200 [KeV].
By injecting approximately 3 to 8×10 ¹⁴ [cm ^-2 ] of
As is well known, the implantation depth of oxygen ions (O ^- ) can be controlled.

Next, the Si substrate 1 is subjected to a heat treatment in a nitrogen (N ₂ ) atmosphere at approximately 750 [°C] for about 6 hours, so that the oxygen ions (O ^- ) 2 are removed as shown in FIG.
By depositing , defect nuclei 3 are formed inside the Si substrate 1 .

Subsequent to the above process, heat treatment is further performed in a nitrogen (N ₂ ) atmosphere at about 1200 [°C] for about 30 [minutes], so that the internal defects 4 center around the defect core 3 as shown in FIG. to occur.
By generating the internal defect 4 in this way,
As is well known, a defect-free layer 5 is formed on the surface of the Si substrate 1.

In this example, as described above, by implanting a desired amount of oxygen ions (O ^- ) to a desired depth to form a defect nucleus, the defect nucleus 3 is formed at a desired depth from the surface of the Si substrate 1. After forming a defect-free layer 5
It is possible to control the thickness to a predetermined thickness, and it is also possible to create a structure in which the defect-free layer on the substrate disappears depending on the crystal growth temperature and time and the subsequent device fabrication process temperature. This differs from conventional manufacturing methods in this point. That is, in the conventional manufacturing method, in the series of heat treatment steps described above, oxygen (O ₂ ) originally contained in the Si substrate 1 is precipitated to form defect nuclei 3', and the Si substrate 1 is Since the defect-free layer 5 was formed on the surface of the Si substrate 1 by generating internal defects 4' throughout the interior, the thickness of the defect-free layer 5 had to vary due to changes in the oxygen concentration contained inside. Ta.

What should be kept in mind in the steps up to this point is to select the thickness of the defect-free layer 5, taking into consideration the diffusion of internal defects 4 due to the heat treatment applied to the Si substrate 1 in the subsequent steps. .

Next, as shown in FIG. 4, the surface of the defect-free layer 5 is etched by vapor phase etching using hydrochloric acid (HCl), and then a predetermined Si single crystal layer 6 is formed by epitaxial growth. In the above vapor phase etching process, it is important to control the etching amount by considering the crystal growth temperature and time so that the remaining defect-free layer 5 has a predetermined thickness. In the example, since the initial thickness of the defect-free layer 5 is sufficiently controlled, the etching control in the vapor phase etching step is also easy.

Thereafter, according to the normal manufacturing process, for example, a gate oxide film 11, n ⁺ type source and drain regions 12, 13, an insulating film 14 such as a silicon dioxide (SiO ₂ ) film, and an aluminum (Al) film are formed. Gate electrodes, source electrodes, drain electrodes 15, 16, 17, etc. made of a conductive material are formed, and the semiconductor device according to this embodiment is completed as shown in FIG.

In the completed semiconductor device of this example obtained as described above, the internal defect layer 4 was diffused into the defect-free layer 5 by the heat treatment in the semiconductor element forming process as described above (see FIG. 5). , almost no unnecessary defect-free layer exists directly under the source region 12 and drain region 13. Therefore, as mentioned above, even if alpha rays enter, the possibility of malfunctions due to the influence can be almost eliminated. At the same time, the epitaxial layer on which the active layer is formed maintains its original crystal defect-free state.

It is already known that if a Si substrate containing a predetermined concentration of oxygen (O ₂ ) etc. is subjected to heat treatment as in the above example, internal defects can be generated in the Si substrate, and the processing conditions Approximately 650
A two-stage heat treatment consisting of a first-stage treatment at ~800 [°C] followed by a second-stage treatment at approximately 1070-1250 [°C], and the first stage treatment. It is also known that the temperature may be lowered once to about 900 [° C.] and then the above-mentioned first stage treatment may be performed. Of course, when carrying out the present invention, the above-mentioned heat treatment conditions may be in accordance with any of the above-mentioned already known conditions.

The present invention is not limited to the one embodiment described above, but can be implemented with various modifications.

That is, the present invention is based on the MIS described in the description of the above embodiment.
It can be used to manufacture not only FETs but also MOS FETs and bipolar semiconductor devices.

Furthermore, carbon (C) may be used instead of oxygen (O ₂ ) as the ions implanted to form defect nuclei.

Furthermore, it goes without saying that the accelerating voltage and dose amount in the ion implantation process can be appropriately selected depending on the purpose.

(f) Effects of the Invention As explained above, the present invention makes it possible to control the thickness of a defect-free layer with good accuracy, and therefore provides a method for manufacturing a semiconductor device that is less affected by alpha rays. be done.

[Brief explanation of drawings]

FIGS. 1 to 5 are sectional views of essential parts of an embodiment of the present invention showing the manufacturing steps thereof in order. In the figure, 1 is a supporting substrate made of silicon (Si), 2 is an implanted ion, 3 is a defect nucleus, 4 is an internal defect, 5 is a defect-free layer, and 6 is an epitaxial growth layer.

Claims (1)

[Claims] 1. Prior to growing a desired silicon single crystal layer on the surface of a silicon support substrate by epitaxial growth, oxygen or carbon is implanted to a predetermined depth into the surface of the silicon support substrate by ion implantation. a step of heating the silicon support substrate at a temperature of 650 [°C] to 800 [°C] to form defect nuclei whose nucleus is oxygen or carbon that can be implanted; ℃〕or
forming a defect-free layer on the surface of the silicon support substrate by performing heat treatment at a temperature of 1250 [°C], and then growing a desired silicon single crystal layer on the defect-free layer by epitaxial growth. Seshime,
A method for manufacturing a semiconductor device, comprising forming a predetermined element in the silicon single crystal layer.