JP4634066B2 - Method for forming a semiconductor layer - Google Patents

Description

  The present invention relates to a method for forming a semiconductor layer.

  Reference 1 (T. Hakkarainen et al., J. Cryst. Growth 234 (2002) pp631.) Describes thermal annealing of GaInNAs semiconductor films in an arsenic atmosphere formed from TBAs in a MOVPE furnace. ing. Since the atmosphere for thermal annealing is formed from TBAs, it contains arsenic and hydrogen.

  Reference 2 (H. Saito et al., J. Cryst. Growth 195 (1998) pp 416.) describes that thermal annealing is performed on GaInNAs / GaAs quantum wells in a nitrogen atmosphere using a dedicated thermal annealing apparatus. Are listed. The temperature lowering process is also performed in a nitrogen atmosphere.

Reference 3 (H. Saito et al., J. Cryst. Growth 195 (1998) pp 416.) describes that a structural change of a GaInNAs semiconductor is caused by thermal annealing.
T. Hakkarainen et al., J. Cryst. Growth 234 (2002) pp631. H. Saito et al., J. Cryst. Growth 195 (1998) pp416. S. Kurtz et al., Appl. Phys. Lett. 78 (2001) pp748.

According to the experiments by the inventors, when a III-V compound semiconductor containing gallium element, indium element, arsenic element and nitrogen element, for example, GaInNAs semiconductor is annealed in an active hydrogen atmosphere, N—H ₂ bond is present in the semiconductor. Is generated, and the optical characteristics of the semiconductor are improved. However, it has been clarified that in the annealing of the semiconductor, the optical characteristics are deteriorated depending on the temperature lowering process.

According to Literature 3, the thermal annealing changes the N—H bond (3101 cm ⁻¹ ) of the GaInNAs semiconductor to the N—H ₂ bond (3124 cm ⁻¹ ). On the other hand, according to Document 2, since the GaInNAs semiconductor film is annealed in an inert gas atmosphere such as nitrogen, thermal annealing in active hydrogen is not performed. When the GaInNAs semiconductor film is annealed in an inert gas atmosphere, hydrogen is easily desorbed, so that the chemical bond change described in Document 3 is less likely to occur.

  According to Reference 1, active hydrogen is supplied for thermal annealing in a TBAs atmosphere, but no contrivance has been made in the temperature lowering process. This degrades the optical characteristics of the GaInNAs semiconductor film in the temperature lowering process. This document does not consider how active hydrogen works for thermal annealing.

  Therefore, the present invention has been made in view of the above matters, and is a semiconductor formed of a III-V compound semiconductor containing gallium element, indium element, arsenic element, and nitrogen element and exhibiting good optical characteristics. The object is to provide a method of forming a layer.

One aspect of the invention relates to a method for forming a semiconductor layer. This method includes (a) forming a semiconductor layer made of a III-V compound semiconductor containing gallium element, indium element, arsenic element and nitrogen element on a gallium arsenide substrate by metal organic vapor phase epitaxy; and (b) Performing a heat treatment on the semiconductor layer in an atmosphere containing active hydrogen; and (c) lowering the temperature from the temperature of the heat treatment in an atmosphere not containing active hydrogen after the heat treatment of the semiconductor layer is completed. The temperature of the heat treatment is 510 degrees Celsius or more, and the temperature of the heat treatment is less than 720 degrees Celsius.

  According to the present invention, after the semiconductor layer is heat-treated in an atmosphere containing active hydrogen, the temperature of the semiconductor layer is lowered from the temperature of the heat treatment in an atmosphere not containing active hydrogen, thereby improving the optical characteristics of the semiconductor layer. Can do.

  According to the present invention, after forming a semiconductor layer made of a III-V compound semiconductor containing a gallium element, indium element, arsenic element and nitrogen element, one or more other semiconductor layers made of a III-V compound semiconductor are formed. The heat treatment may be performed after another semiconductor layer is formed.

  According to this method, after the semiconductor layer is heat-treated in an atmosphere containing active hydrogen, the temperature of the semiconductor layer is lowered from the temperature of the heat treatment in an atmosphere not containing active hydrogen, thereby improving the optical characteristics of the semiconductor layer. In addition to being capable of forming a steep hetero interface.

  In the present invention, the temperature of the heat treatment is preferably 510 degrees Celsius or more, and the temperature of the heat treatment is preferably less than 720 degrees Celsius.

  According to this invention, when the temperature of the heat treatment is 510 degrees Celsius or higher, the optical characteristics of the semiconductor layer are improved. If the heat treatment temperature is 720 degrees Celsius or higher, the optical characteristics of the semiconductor layer cannot be improved.

  In the present invention, it is preferable that in the step of performing a heat treatment on the semiconductor layer, a hydride raw material for forming active hydrogen is supplied to form an atmosphere containing the active hydrogen.

  According to this invention, it is preferable to use a hydride raw material in order to form an atmosphere containing active hydrogen.

In the present invention, the hydride raw material is AsH ₃ , PH ₃ , SiH ₄ , Si ₂ H ₆ , HF, HCl, HBr, HAt, H ₂ O, H ₂ S, H ₂ Se, H ₂ Te, H _{2 Po, NH 3, SbH 3,} BiH 3, CH 4, GeH 4, SnH 3, PbH 3, BH 3, PH 5, AsH 5, SbH 5, SH 4, SH 6, SeH 4, SeH 6, TeH 4, _{TeH 6, IH 3, IH 5} , AlH 3, GaH 3, (CH 3) 3 Al, (C 6 H 15) AlO, (CH 3) 2 AlH, (C 2 H 5) 3 Al, (CH 3) ₃ Sb, (C ₂ H ₅ ) ₃ Sb, C ₆ H ₁₈ N ₃ Sb, (CH ₃ ) ₃ As, C ₆ H ₁₈ N ₃ As, (CH ₃ ) ₃ Bi, (CH ₃ ) ₂ Cd, CHCl ₃ , (CH ₃ ) ₃ Ga, (C ₂ H ₅ ) ₃ Ga, (CH ₃ ) ₃ In, (C ₂ H ₅ ) ₃ In, (C ₅ H ₅ ) ₂ Mg, (C ₆ H ₇ ) ₂ Mg, (CH ₃ ) ₂ NNH ₂ , (CH ₃ ) ₃ CNH ₂ , (CH ₃ ) ₂ Se, (CH ₃ ) ₂ Te, (C ₂ H ₅ ) ₂ Te, (C ₃ H ₇ ) ₂ Te, (C ₂ H ₅ ) ₂ Zn, (CH ₃ ) ₂ Zn, C ₄ H ₁₁ P, C ₄ H ₁₁ As, (C ₂ H ₅ ) ₄ Si, (C ₅ H ₅ ) ₂ Fe, HI, BiH ₃ , C ₂ H ₃ CN, CH ₃ Cl, HCN, CH ₃ Br, C ₂ H ₂ , C ₂ H ₄ , C ₂ H ₆ , C ₃ H ₆ , C ₃ H ₈ , C ₄ H ₆ , C ₄ H _{10, C 6 H 6, (} CH 3) 2 O, B 2 H 6, GeH 4 _{SiH 2 Cl 2, SiHCl 3,} SnH 4, N 2 H 4, may include at least one hydride of CH ₃ NHNH _2.

  According to this invention, an atmosphere containing active hydrogen can be formed using the hydride raw material.

  In the present invention, in the step of performing the heat treatment on the semiconductor layer, the active hydrogen can be generated by forming a plasma of at least one of hydrogen and the hydride by an RF plasma method or an ECR plasma method. .

  According to the present invention, active hydrogen can be efficiently generated by the RF plasma method or the ECR plasma method.

  The above and other objects, features, and advantages of the present invention will become more readily apparent from the following detailed description of preferred embodiments of the present invention, which proceeds with reference to the accompanying drawings.

  As described above, according to the present invention, there is provided a method for forming a semiconductor layer of a III-V compound semiconductor containing gallium element, indium element, arsenic element, and nitrogen element and exhibiting good optical characteristics.

The knowledge of the present invention can be easily understood by considering the following detailed description with reference to the accompanying drawings shown as examples. Subsequently, embodiments of the method for forming a semiconductor layer of the present invention will be described with reference to the accompanying drawings. Where possible, the same parts are denoted by the same reference numerals.
(First embodiment)
1A, 1B, and 1C illustrate an embodiment of a method for forming a semiconductor layer of a III-V compound semiconductor containing a gallium element, an indium element, an arsenic element, and a nitrogen element. FIG.

As shown in FIG. 1A, a semiconductor layer made of a III-V compound semiconductor containing a gallium element, an indium element, an arsenic element, and a nitrogen element is formed. A semiconductor substrate 11 is prepared. The semiconductor substrate 11 is disposed in a film forming apparatus 17 such as a low pressure metal organic chemical vapor deposition (MOVPE) apparatus. In this embodiment, the semiconductor substrate 11 can be, for example, a gallium arsenide substrate having a (100) plane. A gallium arsenide semiconductor film 13 is epitaxially grown on the gallium arsenide substrate. The gallium arsenide semiconductor film 13 is deposited using a source gas containing triethylgallium (TEGa) and tertiarybutylarsine (TBAs) and a carrier gas containing hydrogen, for example. On the gallium arsenide semiconductor film 13, a III-V compound semiconductor containing gallium element, indium element, arsenic element and nitrogen element, for example, a GaInNAs semiconductor film 15 is epitaxially grown. The GaInNAs semiconductor film 15 is deposited using, for example, a source gas containing triethylgallium (TEGa), trimethylindium (TMIn), tertiarybutylarsine (TBAs) and dimethylhydrazine (DMHy) and a carrier gas containing hydrogen. After the deposition of the semiconductor films 13 and 15 is completed, the temperature of the substrate is changed from the temperature T _Dep for film formation to the temperature T _Ann for thermal annealing.

As shown in FIG. 1B, the semiconductor layer is heat-treated at a thermal annealing temperature T _Ann . This heat treatment 19 can be performed using, for example, a film forming apparatus. The heat treatment 19 is performed in an atmosphere 21 containing active hydrogen 23. In order to prevent arsenic escape from the semiconductor layers 13 and / or 15, the atmosphere 21 preferably contains arsenic vapor 25. The temperature T _{Ann of the} heat treatment 19 is preferably 510 degrees Celsius or higher. When the temperature T _{Ann of the} heat treatment 19 is 510 degrees Celsius or higher, the optical characteristics of the semiconductor device are improved. The temperature T _{Ann of the} heat treatment 19 is preferably less than 720 degrees Celsius. When the temperature T _{Ann of the} heat treatment is 720 degrees Celsius or higher, the optical characteristics of the semiconductor device are not improved. According to this method, a nitride semiconductor film having good optical characteristics at a relatively low temperature can be obtained. Further, it is advantageous for forming an epitaxially grown film having a good quality heterointerface with less burden on manufacturing equipment and less interdiffusion.

In the step of performing the heat treatment 19 on the semiconductor layers 13 and 15, an atmosphere 21 containing active hydrogen 23 can be formed by supplying a hydride raw material such as tertiary butylarsine. By using a hydride raw material, an atmosphere containing active hydrogen can be formed according to the film formation environment. The hydride raw material is not limited to these, and exemplarily listed, the hydride raw material is AsH ₃ , PH ₃ , SiH ₄ , Si ₂ H ₆ , HF, HCl, HBr, HAt, H ₂ O, H ₂ S, H ₂ Se, H ₂ Te, H ₂ Po, NH ₃ , SbH ₃ , BiH ₃ , CH ₄ , GeH ₄ , SnH ₃ , PbH ₃ , BH ₃ , PH ₅ , AsH ₅ , SbH _{5 , SH 4, SH 6, SeH} 4, SeH 6, TeH 4, TeH 6, IH 3, IH 5, AlH 3, GaH 3, (CH 3) 3 Al, (C 6 H 15) AlO, (CH 3) ₂ AlH, (C ₂ H ₅ ) ₃ Al, (CH ₃ ) ₃ Sb, (C ₂ H ₅ ) ₃ Sb, C ₆ H ₁₈ N ₃ Sb, (CH ₃ ) ₃ As, C ₆ H ₁₈ N ₃ As , (CH ₃ ) ₃ Bi, (CH ₃ ) ₂ Cd, CHCl ₃ , (CH ₃ ) ₃ Ga, (C ₂ H ₅ ) ₃ Ga, (CH ₃ ) ₃ In, (C ₂ H ₅ ) ₃ In, (C ₅ H ₅ ) ₂ Mg, (C ₆ H ₇ ) ₂ Mg, (CH ₃ ) ₂ NNH ₂ , (CH ₃ ) ₃ CNH ₂ , (CH ₃ ) ₂ Se, (CH ₃ ) ₂ Te, (C ₂ H ₅ ) ₂ Te, (C ₃ H ₇ ) ₂ Te, (C ₂ H ₅ ) ₂ Zn, (CH ₃ ) ₂ Zn, C ₄ H ₁₁ P, C ₄ H ₁₁ As, (C ₂ H ₅ ) ₄ Si, (C ₅ H ₅ ) ₂ Fe, HI, BiH ₃ , C ₂ H ₃ CN, CH ₃ Cl, HCN, CH ₃ Br, C ₂ H ₂ , C ₂ H ₄ , C ₂ H ₆ , C ₃ H ₆ , C ₃ H ₈ , C ₄ H ₆ , C ₄ H ₁₀ , C ₆ H ₆ , (CH ₃ ) ₂ O, B ₂ H ₆ , GeH ₄ , SiH ₂ Cl ₂ , SiHCl ₃ , SnH ₄ , N ₂ H ₄ , At least one hydride of CH ₃ NHNH ₂ may be included. In one embodiment, the hydride pressure is preferably 10 Pascals or more and 101300 Pascals or less. An atmosphere containing active hydrogen can be formed using the hydride raw material. After the thermal annealing is completed, the active hydrogen is removed from the chamber of the apparatus used for the thermal annealing to form an atmosphere containing no active hydrogen.

As shown in FIG. 1C, the heat-treated semiconductor films 13a and 15a are provided by the thermal annealing 19. After the heat treatment of the semiconductor layer, the temperature is changed from the heat treatment temperature T _{Ann in} an atmosphere containing no active hydrogen. This temperature change includes lowering the temperature of the semiconductor layer from the temperature of the heat treatment in the atmosphere 27 containing no active hydrogen. Such a temperature decrease can improve the optical characteristics of the semiconductor layer.

  In this embodiment, after forming the semiconductor layer 15 made of a III-V compound semiconductor containing gallium element, indium element, arsenic element and nitrogen element, one or more other semiconductor layers made of III-V compound semiconductor are formed. Can be formed. The heat treatment is performed after another semiconductor layer is formed. According to this method, after the semiconductor layers are heat-treated in an atmosphere containing active hydrogen, the temperature of these semiconductor layers is lowered from the temperature of the heat treatment in an atmosphere containing no active hydrogen. Therefore, in addition to improving the optical characteristics of the semiconductor layer, a steep hetero interface can be formed.

  In the above embodiment, the heat treatment atmosphere containing active hydrogen and arsenic is generated using tertiary butylarsine. The generation of active hydrogen is not limited to this method. FIGS. 2A and 2B are drawings showing an embodiment of a method for forming a semiconductor layer of a III-V compound semiconductor according to a modification of the present embodiment. In these modified examples, after forming a III-V compound semiconductor film containing gallium element, indium element, arsenic element, and nitrogen element, thermal annealing 19 is performed in hydrogen plasma. In the modification of the present embodiment, as shown in FIG. 2A, the plasma 33 of at least one of hydrogen and hydride can be formed by the RF plasma apparatus 31. Active hydrogen can be efficiently generated by the RF plasma method. Further, as shown in FIG. 2B, a plasma 37 of at least one of hydrogen and hydride can be formed by an ECR plasma apparatus 35. Active hydrogen can be efficiently generated by the ECR plasma method. The advantage as ECR plasma is that damage to the epitaxial crystal can be reduced as compared with the RF plasma method.

  The common advantages of RF and ECR plasma are shown below. Advantages: (1) When hydrogen or hydride raw material that is difficult to be thermally decomposed is used, the plasma method can efficiently generate active hydrogen. (2) By generating active hydrogen by plasma method using non-toxic gas such as hydrogen, it is easy to anneal in an inexpensive heat treatment furnace instead of expensive equipment such as MOVPE equipment with abatement equipment. There is a merit that you can.

  3A, 3B, and 3C are views showing a method of forming a GaInNAs semiconductor layer according to the above-described embodiment. FIGS. 3D, 3E, and 3F are diagrams illustrating a method of forming a GaInNAs semiconductor layer described in Document 1 and Document 3. FIG.

As shown in FIG. 3A, the GaInNAs semiconductor layer 47 provided on the substrate 41 (including the GaAs wafer 43 and the GaAs buffer layer 45) includes N—H bonds 49. As shown in FIG. 3B, by performing thermal annealing in an atmosphere of active hydrogen 51, the N—H bond is changed to the N—H ₂ bond 53 by the action of the active hydrogen 51. According to the experiments by the inventors, the GaInNAs semiconductor layer 47 including a large number of N—H ₂ bonds 53 exhibits good optical characteristics. In the annealing in an active hydrogen atmosphere, N—H ₂ bonds are generated and the optical characteristics are improved. However, if active hydrogen 51 is supplied when the temperature is lowered, the optical characteristics of the semiconductor film are deteriorated. Or the active hydrogen 51 is mixed while cooled to form a N-H bond, or it may be returned to the N-H bond breaking the N-H ₂ bonds. As shown in FIG. 3C, the GaAs buffer layer 45a and the GaInNAs semiconductor layer 47a are obtained by changing the temperature in an atmosphere not containing the active hydrogen 51. There is little decrease in the number of N—H ₂ bonds formed in the GaInNAs semiconductor layer 47a.

On the other hand, in the method for forming a GaInNAs semiconductor layer described in Document 1 and Document 3, as shown in FIG. 3D, the GaInNAs semiconductor layer 47 provided on the substrate 41 has N—H bonds. included. By performing thermal annealing in an active hydrogen atmosphere, a GaAs buffer layer 45a and a GaInNAs semiconductor layer 47a are formed. The N—H bond 49 is changed to the N—H ₂ bond 51 by the action of active hydrogen. However, since the active hydrogen has the opposite effect when the temperature is lowered, the GaAs buffer layer 45b and the GaInNAs semiconductor layer 47b are formed when the temperature is lowered in an atmosphere containing active hydrogen. In these semiconductor films 45 b and 47 b, some of the formed N—H ₂ bonds are changed to N—H bonds 55 by the action of the active hydrogen 51. In the method of Document 2, active hydrogen is not supplied during thermal annealing. Since the N—H bond breaks from around 500 degrees Celsius (above this temperature), hydrogen is desorbed from the crystal when no active hydrogen is supplied during thermal annealing at 500 degrees Celsius or more. When hydrogen is desorbed, N—H ₂ bonds cannot be generated, and the effect cannot be obtained.

4A and 4B are diagrams illustrating the structure of a semiconductor device of an experimental example.
(Experimental example 1)
A GaInNAs epitaxial film lattice-matched to GaAs is grown by a low pressure MOVPE method. TEGa, TMIn, DMHy, and TBAs are used as raw materials for gallium (Ga), indium (In), nitrogen (N), and arsenic (As), respectively. A Si-doped GaAs substrate (twice off) having a (100) plane is used as the substrate. The growth temperature is 510 degrees Celsius. The growth rate is 1.0 micrometers per hour, the DMHy / V group molar ratio is 0.97, and the growth pressure is 10130 Pascal (76 Torr). As shown in FIG. 4A, an epitaxial film having a GaInNAs / GaAs structure is formed on a GaAs substrate. For example, the thickness of the GaInNAs film is 0.3 micrometers, the GaInNAs film is 14% indium, nitrogen. It has a composition of 5 percent.

After the GaInNAs epitaxial film is grown, this film is subjected to in-situ thermal annealing using a MOVPE furnace. The heat treatment was performed using a MOVPE furnace in a TBAs atmosphere (TBAs flow rate was 1.6 × 10 ⁻⁴ moles per minute (mole / min)), and the thermal annealing temperatures were 595 degrees Celsius and 670 degrees Celsius, respectively. The thermal annealing time is 10 minutes. After the thermal annealing, the supply of TBAs is stopped and the temperature is lowered in an atmosphere not containing hydrogen. Further, thermal annealing of the GaInNAs epitaxial film is performed using a dedicated heat treatment furnace. Thermal annealing in a dedicated heat treatment furnace is performed at a temperature of 600 degrees Celsius in an As atmosphere in which a solid As raw material is sublimated, and the thermal annealing time is 30 minutes.

FIG. 5 is a graph showing the measurement results of Fourier transform infrared absorption spectra (FTIR) of these GaInNAs semiconductor films. The horizontal axis indicates the wave number (cm ⁻¹ ), and the vertical axis indicates the infrared absorption intensity (arbitrary unit). Characteristic curves C1, C2, C3, and C4 are shown in the graph. The absorption peak in each characteristic curve is related to NH vibration at 3125 cm ⁻¹ . FIG. 6 is a drawing showing the relationship between the absorption peak intensity of FTIR and the photoluminescence (PL) intensity. The horizontal axis represents photoluminescence intensity (arbitrary unit), and the vertical axis represents infrared absorption intensity (arbitrary unit). Measurement points M1 and M2 indicate data (in-situ) corresponding to thermal annealing in an atmosphere containing active hydrogen and temperature drop in an atmosphere not containing active hydrogen. A measurement point M3 indicates data corresponding to thermal annealing and temperature lowering in an atmosphere without active hydrogen. The measurement point M4 indicates data (as-grown) without thermal annealing. As shown in FIG. 6, in the GaInNAs crystal, the absorption peak intensity and the PL intensity have a positive correlation. Formation of N—H ₂ bonds reduces non-luminescent centers and improves the optical properties of GaInNAs crystals.

(Experimental example 2)
As shown in FIG. 4B, a GaInNAs / GaAs single quantum well (SQW) structure is formed by a low pressure MOVPE method. In a semiconductor device having a quantum well structure, the GaInNAs film is 7 nanometers thick, and the GaInNAs film has a 34 percent indium composition and a 1 percent nitrogen composition. TEGa, TMIn, DMHy, and TBAs are used as raw materials for gallium (Ga), indium (In), nitrogen (N), and arsenic (As), respectively. A Si-doped GaAs substrate (twice off) having a (100) plane is used as the substrate. The growth temperature is 510 degrees Celsius. The growth rate is 0.9 micrometers per hour, the DMHy / V group molar ratio is 0.99, and the growth pressure is 10130 Pascals (76 Torr).

After the GaInNAs / GaAs quantum well epitaxial film is grown, in-situ thermal annealing is performed using a MOVPE furnace. The heat treatment in the MOVPE furnace is performed in a TBAs atmosphere (TBAs flow rate is 1.6 × 10 ⁻⁴ mol / mole / min), and thermal annealing is performed at temperatures of 570 degrees Celsius, 670 degrees Celsius, and 720 degrees Celsius, respectively. The thermal annealing time is 10 minutes. After the thermal annealing, the supply of TBAs is stopped and the temperature is lowered in an atmosphere containing no active hydrogen. On the other hand, the quantum well epitaxial film is thermally annealed using a dedicated heat treatment furnace. In thermal annealing in a dedicated heat treatment furnace, the GaInNAs film is covered with a GaAs substrate in order to prevent arsenic desorption from the surface of the GaInNAs film. Thermal annealing is performed in a nitrogen gas atmosphere at several temperatures ranging from 500 degrees Celsius to 780 degrees Celsius, and the thermal annealing time is 15 seconds.

FIG. 7 is a graph showing the results of measuring the photoluminescence (PL) characteristics of these GaInNAs / GaAs quantum wells at room temperature. The horizontal axis indicates the thermal annealing temperature (Celsius), and the vertical axis indicates the photoluminescence intensity (arbitrary unit). The symbol “■” indicates the PL intensity of a quantum well fabricated by performing thermal annealing in a nitrogen atmosphere and then lowering the temperature in the nitrogen atmosphere. The symbol “□” indicates the PL intensity of a quantum well produced by performing thermal annealing in an atmosphere containing active hydrogen (TBAs atmosphere) and then lowering the temperature in an atmosphere containing no active hydrogen. According to the dependence of the PL strength on the thermal annealing temperature, there is an optimum thermal annealing temperature that maximizes the PL strength in each of thermal annealing in an atmosphere containing active hydrogen and thermal annealing in an atmosphere not containing active hydrogen. In thermal annealing (thermal annealing performed in a MOVPE furnace) in an atmosphere (TBAS atmosphere), the temperature is about 670 degrees Celsius. In thermal annealing in a nitrogen atmosphere without active hydrogen (thermal annealing performed in a dedicated heat treatment furnace), It is 600 degrees Celsius. The PL strength of quantum wells annealed in an active hydrogen atmosphere is strong. Comparing the PL intensity in these thermal annealing, the PL intensity of the quantum well annealed in the active hydrogen atmosphere is about 4 times larger than the PL intensity of the quantum well annealed in the atmosphere without active hydrogen. Thermal annealing in an active hydrogen atmosphere is advantageous for improving the optical properties of GaInNAs crystals. As this factor, it is considered that the non-luminescent center is reduced by the formation of N—H ₂ bond in the active hydrogen atmosphere annealing. Therefore, good optical properties can be obtained unless the number of bonds is increased and decreased.

  As described above, according to the embodiment of the present invention, a method for forming a semiconductor layer of a III-V compound semiconductor containing gallium element, indium element, arsenic element, and nitrogen element and exhibiting good optical characteristics is provided. it can.

  In this embodiment mode, a method for forming a GaInNAs semiconductor film has been described. It can be used to improve the optical properties of InPN, InPAsN, and GaPAsN semiconductor films. In the present embodiment, the quantum well semiconductor device having the SQW structure has been described. However, this method is also used for a semiconductor device having a quantum well structure having a multiple quantum well structure (MQW).

  While the principles of the invention have been illustrated and described in the preferred embodiments, it will be appreciated by those skilled in the art that the invention can be modified in arrangement and detail without departing from such principles. The present invention is not limited to the specific configuration disclosed in the present embodiment. For example, the method of forming a semiconductor device according to the present invention can be used in a method of manufacturing a semiconductor device. Semiconductor devices include semiconductor optical elements such as laser diodes, light emitting diodes, photodiodes, semiconductor amplifiers, solar cells, and light modulation elements. We therefore claim all modifications and changes that come within the scope and spirit of the following claims.

1A, 1B, and 1C illustrate an embodiment of a method for forming a semiconductor layer of a III-V compound semiconductor containing a gallium element, an indium element, an arsenic element, and a nitrogen element. FIG. FIGS. 2A and 2B are diagrams showing an embodiment of a method for forming a semiconductor layer of a III-V compound semiconductor according to a modification of the present embodiment. 3A, 3B, and 3C are views showing a method of forming a GaInNAs semiconductor layer according to the above-described embodiment. FIGS. 3D, 3E, and 3F are diagrams illustrating a method of forming a GaInNAs semiconductor layer described in Document 1 and Document 3. FIG. 4A and 4B are diagrams showing the structure of a semiconductor multilayer film of an experimental example. FIG. 5 is a graph showing a measurement result of a Fourier transform infrared absorption spectrum (FTIR) of the GaInNAs semiconductor film in Experimental Example 1. FIG. 6 is a drawing showing the relationship between the absorption peak intensity of FTIR and the photoluminescence (PL) intensity in Experimental Example 1. FIG. 7 is a graph showing the results of measuring the photoluminescence (PL) characteristics of GaInNAs / GaAs quantum wells in Experimental Example 2 at room temperature.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Semiconductor substrate, 13 ... Gallium arsenide semiconductor film, 15 ... GaInNAs semiconductor film, 17 ... Film-forming apparatus,
19 ... heat treatment, 23 ... active hydrogen, 21 ... atmosphere containing active hydrogen, 13a, 15a ... heat treated semiconductor film, T _Ann ... temperature of heat treatment, T _Dep ... temperature of deposition, 27 ... atmosphere containing no active hydrogen, 41 ... substrate, 43 ... GaAs wafer, 45 ... GaAs buffer layer, 47 ... GaInNAs semiconductor layer, 51 ... active hydrogen, 53 ... _{N-H 2} bonds, 55 ... N-H bonds, in an atmosphere free of 45a ... active hydrogen GaAs buffer layer lowered in temperature, 47a ... GaInNAs semiconductor layer lowered in an atmosphere containing no active hydrogen, 45b ... GaAs buffer layer lowered in an atmosphere containing active hydrogen, 47b ... in an atmosphere containing active hydrogen Temperature-lowered GaInNAs semiconductor layer

Claims (5)

A method for forming a semiconductor layer, comprising:
Forming a semiconductor layer made of a III-V compound semiconductor containing gallium element, indium element, arsenic element and nitrogen element on a gallium arsenide substrate by metal organic vapor phase epitaxy;
Applying a heat treatment to the semiconductor layer in an atmosphere containing active hydrogen;
After the heat treatment of the semiconductor layer is completed, a step of lowering the temperature of the heat treatment in an atmosphere containing no active hydrogen,
The temperature of the heat treatment is 510 degrees Celsius or higher,
The temperature of the heat treatment is less than 720 degrees Celsius. Forming a semiconductor layer made of a III-V compound semiconductor containing a gallium element, an indium element, an arsenic element, and a nitrogen element, and then forming one or more other semiconductor layers made of a III-V compound semiconductor;
The method according to claim 1, wherein the heat treatment is performed after forming the another semiconductor layer. The method according to claim 1, wherein the atmosphere in the step of performing a heat treatment on the semiconductor layer includes arsenic in addition to the active hydrogen. 4. The method according to claim 1, wherein, in the step of performing a heat treatment on the semiconductor layer, an hydride raw material for forming active hydrogen is supplied to form an atmosphere containing the active hydrogen. 5. The method according to one item. The hydride raw materials are AsH ₃ , PH ₃ , SiH ₄ , Si ₂ H ₆ , HF, HCl, HBr, HAt, H ₂ O, H ₂ S, H ₂ Se, H ₂ Te, H ₂ Po, NH _{3 , SbH 3, BiH 3, CH} 4, GeH 4, SnH 3, PbH 3, BH 3, PH 5, AsH 5, SbH 5, SH 4, SH 6, SeH 4, SeH 6, TeH 4, TeH 6, IH ₃ , IH ₅ , AlH ₃ , GaH ₃ , (CH ₃ ) ₃ Al, (C ₆ H ₁₅ ) AlO, (CH ₃ ) ₂ AlH, (C ₂ H ₅ ) ₃ Al, (CH ₃ ) ₃ Sb, ( C ₂ H ₅ ) ₃ Sb, C ₆ H ₁₈ N ₃ Sb, (CH ₃ ) ₃ As, C ₆ H ₁₈ N ₃ As, (CH ₃ ) ₃ Bi, (CH ₃ ) ₂ Cd, CHCl ₃ , (CH ₃ ) ₃ Ga, (C ₂ H ₅ ) ₃ Ga, (CH ₃ ) ₃ In, (C ₂ H ₅ ) ₃ In, (C ₅ H ₅ ) ₂ Mg, (C ₆ H ₇ ) ₂ Mg, (CH _{3) 2 NNH 2, (CH} 3) 3 CNH 2, (CH 3) 2 Se, (CH 3) 2 Te, (C 2 H 5) 2 Te, (C 3 H 7) 2 Te, (C 2 H ₅ ) ₂ Zn, (CH ₃ ) ₂ Zn, C ₄ H ₁₁ P, C ₄ H ₁₁ As, (C ₂ H ₅ ) ₄ Si, (C ₅ H ₅ ) ₂ Fe, HI, BiH ₃ , C ₂ H ₃ CN, CH ₃ Cl, HCN, CH ₃ Br, C ₂ H ₂ , C ₂ H ₄ , C ₂ H ₆ , C ₃ H ₆ , C ₃ H ₈ , C ₄ H ₆ , C ₄ H ₁₀ , C ₆ H ₆ , (CH ₃ ) ₂ O, B ₂ H ₆ , GeH ₄ , SiH ₂ Cl ₂ , SiH _{Cl 3, SnH 4, N 2} H 4, CH 3 method according to claim 4, characterized in that it comprises at least one hydride of NHNH _2.

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