JP2006013269A - Device and method for vapor phase epitaxy - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vapor phase epitaxy device and vapor phase epitaxy method wherein material gas can be supplied uniformly to a substrate without disturbance of the flow of gas, vapor phase epitaxy can be effected continuously without necessitating the cleaning of a reaction pipe, crystal growth can be effected under a condition coping with the growth film of a nitride compound semiconductor, crystallinity is maintained even when the semiconductor film is formed at high temperatures under reduced amount of gas, and the re-degradation of the growth crystal is prevented. <P>SOLUTION: In the reaction pipe 100 having a susceptor 102 for mounting the substrate 101 and a heater 103 for heating the susceptor 102, vapor phase epitaxy is carried out at the temperature of T1+T2 by heating the susceptor at the temperature of T1 and by heating the surface of the substrate 101 by a temperature T2 further through a heating means 115. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a semiconductor film vapor phase growth apparatus and a vapor phase growth method.

Conventionally, this kind of apparatus is shown by patent document 1, for example. According to this Patent Document 1, an organic metal gas such as trimethylgallium is used as a group III metal source, ammonia is used as a nitrogen source, introduced from a raw material introduction tube onto a substrate such as sapphire previously set in a reaction tube, and heated. Vapor phase growth is performed on the formed substrate.
Japanese Patent Laid-Open No. 10-12624

In the above apparatus, decomposition products or reaction products are deposited on the reaction tube wall facing the substrate by thermal convection generated by heating the gas containing the raw material on the substrate, contaminating the reaction tube, and depositing solids There is a first drawback in that an object falls on the substrate and the reaction does not proceed in the place where it falls.
Further, when the p-GaAlN layer and the p-GaN layer were formed at a high temperature to form the p-GaAlN cladding layer and the p-GaN contact layer, they were formed below the p-GaAlN layer and the p-GaN layer. There is a second drawback in that the InN constituting the InGaN light emitting layer is decomposed and the light emission output is deteriorated. In addition, the growth temperature of the p-GaAlN layer and the p-GaN layer must be lowered, the hole concentration is decreased, the resistance of the p-layer region is increased, and the resistance between the p-GaN layer and the p-electrode is increased. There are three drawbacks.

  Therefore, the present invention takes into account such conventional drawbacks, and has a light emitting layer that hardly contaminates the reaction tube wall and does not deteriorate the crystal, and is suitable for reducing the resistance of the p-GaN layer and the p electrode. Provided are a vapor deposition apparatus and a vapor deposition method for a semiconductor film.

  In order to solve the above problems, in the present invention of claim 1, in a vapor phase growth apparatus having a susceptor for placing a substrate and a heater for heating the susceptor, the temperature of the susceptor is T1, and the substrate Further, T2 is heated by the heating means on the surface, so that vapor phase growth is performed at a temperature of T1 + T2.

In the present invention of claim 2, in a vapor phase growth apparatus having a susceptor for placing a substrate and a heater for heating the susceptor, the temperature of the susceptor is set to T3, and the susceptor is irradiated with infrared light from above. By further heating the temperature of the substrate surface by T4, vapor phase growth is performed at a temperature of T3 + T4.
In this invention of Claim 3, it arrange | positions so that it may become substantially parallel to the said board | substrate inside a reaction tube, the heater for heating this susceptor, and the said susceptor, 1st type gas A partition portion having an introduction portion and a discharge portion for the second type gas at the upper portion, and an opening portion located above the substrate is provided in the partition portion. A substrate surface heating means was provided outside the reaction tube located at the top.
In this invention of Claim 4, it arrange | positions so that it may be substantially parallel to the said susceptor for mounting a board | substrate, the heater for heating this susceptor, and the said board | substrate inside reaction tube, and it is 1st type gas in the lower part A partition portion having an introduction portion and a discharge portion for the second type gas at the upper portion, and an opening portion located above the substrate is provided in the partition portion. An infrared light source was provided outside the reaction tube located at the top for heating the substrate surface.
In the present invention of claim 5, the growth gas 1 is used as the first type gas, the growth gas 2 is used as the second type gas, and the growth gas 1 is applied to the surface of the substrate by the lateral pressure of the growth gas 2. Press and grow.
In the present invention of claim 6, an organic group III metal is used as the first type gas, a nitridation-containing hydrocarbon is used as the second type gas, and the first type gas is caused by a lateral pressure of the second type gas. Press against the surface of the substrate to grow.
In this invention of Claim 7, it has the susceptor for mounting a board | substrate, and the heater for heating this susceptor, the temperature of the said susceptor is set to T1, and further T2 heating is carried out by the heating means of the said substrate surface, Vapor phase growth is performed at a temperature of T1 + T2.
In this invention of Claim 8, it has the introduction part and discharge part of 1st type gas in the lower part inside reaction tube, has the introduction part and discharge part of 2nd type gas in the upper part, As said 1st type gas An organic group III metal is used, a nitridation-containing hydrocarbon is used as the second type gas, the first type gas is pressed against the surface of the substrate by a side pressure of the second type gas, and a gas phase is formed at a temperature of T1 + T2. Grow.
In the present invention of claim 9, the n-layer region gallium nitride compound semiconductor is formed at the temperature of T1 + T2.
In the present invention of claim 10, the p-layer region gallium nitride compound semiconductor is formed at the temperature of T1 + T2.
In the present invention of claim 11, the light emitting layer region gallium nitride compound semiconductor is formed at the temperature of T1 + T2.
According to the invention of claim 12, the n-layer region is composed of a multilayer film composed of an n-type GaN layer and an n-type Ga _1-b Al _b N layer (where 0 ≦ b ≦ 1).
In a thirteenth aspect of the present invention, the p-layer region is composed of a multilayer film composed of a p-type GaN layer and a p-type Ga _1-b Al _b N layer (where 0 ≦ b ≦ 1).
In the present invention of claim 14, the light emitting layer region is composed of a film composed of an In _b Ga _1-b N layer (where 0 ≦ b ≦ 1).

According to the vapor phase growth apparatus and the vapor phase growth method of the present invention, the partition wall facing the vapor phase growth substrate is eliminated, a lateral pressure is applied to the organic group III metal gas with a nitriding-containing hydrocarbon gas, and the source gas is supplied to the substrate. The organic group III metal gas and the nitrogen-containing hydrocarbon gas are reacted by pressing. As a result, although not at high speed, the reaction is sufficiently advanced to grow crystals, and the solid wall does not fall on the substrate without contaminating the reaction tube wall. Therefore, there is no need to clean the reaction tube, continuous vapor phase growth can be performed, the source gas can be supplied uniformly on the substrate, and the source gas is suppressed on the substrate by the side pressure. There can be no vapor deposition.
Moreover, since ammonia is not used as a nitrogen supply source, the generation of by-products can be reduced, and the vapor phase growth of a nitride compound semiconductor can be performed with a consumption amount of 1/3 that of ammonia and a small amount of source gas. .
Further, the infrared rays irradiated from outside the reactor are used to heat the substrate surface to a temperature higher than the substrate temperature heated by the heater to re-decompose the formation layer while vapor-depositing a nitride compound semiconductor film on the substrate surface. Therefore, an n-type contact layer and an n-type clad layer can be grown without any crystal deterioration.
Since ammonia is not used as a nitrogen supply source, hydrogen can be used as a carrier gas when forming a light emitting layer, so that crystallinity is improved, and vapor phase growth capable of incorporating In even at high temperature growth can be performed. As a result, when forming the p-cladding layer and the p-contact layer, the hole concentration is increased without lowering the growth temperature, the resistivity of the p region is lowered, and the resistance between the p-contact layer and the p electrode is lowered. can get.

  A vapor phase growth apparatus 92 according to the best mode for carrying out the present invention will be described below with reference to FIG. FIG. 1 is a schematic diagram showing a basic configuration of the vapor phase growth apparatus 92.

As shown in FIG. 1, a susceptor 102 that holds, rotates, and heats a 1-inch n-GaN substrate 101 in a quartz reactor 100 having a width of 150 mm, a height of 20 mm, and a length of 250 mm. A heater 103 for heating the susceptor 102 is provided.
Arranged so as to be substantially parallel to the substrate 101, the lower part has an introduction part 104 for the first kind gas 108 and an exhaust part 105 for the first kind gas 108, and the second kind gas 109 is introduced at the upper part. The partition part 114 and 110 which have the part 106 and the discharge part 107 of the 2nd type gas 109 are provided. An opening 111 is formed in the partition 114 above the substrate 101, and a protruding part 112 of the second type gas 106 is formed below the opening 111.
The characteristics of the configuration of the vapor phase growth apparatus 92 will be described below. A susceptor 102 for placing the substrate 101 and a heater 103 for heating the susceptor 102 are provided. Then, the temperature of the susceptor 102 is set to T1, and T2 is further heated by a heating means (not shown) on the surface of the substrate 101, so that vapor phase growth is performed at a temperature of T1 + T2.

Further, the temperature of the susceptor 102 is T3, and vapor phase growth is performed at a temperature of T3 + T4 by further heating the surface temperature of the substrate 101 by T4 in accordance with infrared light irradiation from the upper part of the susceptor 102.
Furthermore, a susceptor 102 for placing the substrate 101 and a heater 103 for heating the susceptor 102 are provided. Arranged so as to be substantially parallel to the substrate 101 inside the reaction furnace 100, the lower part has the introduction part 104 of the first type gas 108 and the discharge parts 113 and 105, and the introduction part of the second kind gas 109 at the upper part. Partition portions 114 and 110 having 106 and a discharge portion 107 are provided. In the partitions 114 and 110, an opening 111 located above the substrate 101 is provided, located above the opening 111, and a substrate surface heating means is provided outside the reaction furnace 100. As the substrate surface heating means, for example, an infrared light source 115 is provided.
In this vapor phase growth apparatus 92, the growth gas 1 is used as the first type gas 108, the growth gas 2 is used as the second type gas 109, and the growth gas 1 is applied to the surface of the substrate 101 by the side pressure 109A of the growth gas 2. Press to grow.
An organic group III metal is used as the first type gas 108, a nitridation-containing hydrocarbon is used as the second type gas 109, and the first type gas 108 is applied to the surface of the substrate 101 by the side pressure 109A of the second type gas. It is configured to push and grow.

  In FIG. 1, a part of the second type gas 109 proceeds downward along the boundary surface 90 and serves as a side pressure (a gas that collides to the side) 109 </ b> A for the first type gas 108. After the first type gas 108 is grown, these reacted gases are discharged from the discharge portions 113 and 105 along the boundary surface 91.

  Next, the vapor phase growth method according to the best mode 1 for carrying out the present invention will be described with reference to FIGS. FIG. 2 is a schematic diagram of an n-contact layer. In FIG. 1, after setting the n-GaN substrate 101 on the susceptor 102, the inside of the reaction furnace 100 is replaced with hydrogen gas.

Then, from the introduction part 104 of the first type gas 108, nitrogen gas 3.5 L / min and trimethyl gallium (TMG) Ga (CH ₃ ) ₃ as 30 μ-mol / min and the n-type dopant are used as the first type gas 108. In order to dope Si, silane gas (SiH ₄ ) having a concentration of 1 ppm diluted with hydrogen is supplied.

While supplying the above, as the second type gas 109, while supplying 0.1 mol / min of trimethylamine N (CH ₃ ) ₃ which is one kind of nitriding-containing hydrocarbon and 3.5 L / min of nitrogen gas, the substrate 101 is heated to 550 ° C. with a heater 103. Then, light from the infrared light source 115 is reflected on the substrate surface of the n-GaN substrate 101 by the reflection plate 116, and the surface of the substrate 101 is further heated at 450 ° C. Then, a 4 μm n-GaN contact layer 117 shown in FIG. 2 was formed at 1000 ° C.
Since the reaction of trimethylamine is slower than that of ammonia, the substrate 101 is preheated to 550 ° C. by the heater 103. Then, the flow rate control of the trimethylamine gas of the second type gas 109 (the flow rate of the exhausted portion 107 of the reacted gas is reduced) is performed below the opening 111 of the reaction furnace 100 in FIG.

  Thereby, a protruding portion 112 of the trimethylamine gas 109 is formed, a side pressure 109A is added to the trimethylgallium gas of the first type gas 108, and the trimethylamine gas of the second type gas 109 and the trimethylgallium gas of the first type gas 108 are n -It is pressed against the GaN substrate 101. Therefore, since the trimethylamine gas of the second kind gas 109 and the trimethylgallium gas of the first kind gas 108 are heated to 1000 ° C. when they contact the surface of the substrate 101, thermal convection is suppressed.

  Since the grown n-GaN contact layer 117 is covered with the trimethylamine gas 109, re-decomposition of nitrogen is suppressed. More specifically, since the substrate 101 is heated to 550 ° C. by the heater 103 in advance, the trimethylgallium gas 108 and the trimethylamine gas 109 come into contact with the surface of the substrate 101.

At that moment, the light from the infrared light source 115 is reflected by the reflector 116 and further heated to 450 ° C., so that crystal growth proceeds at a growth temperature of 1000 ° C. At a growth temperature of 1000 ° C., trimethylamine 109 decomposes, active nitrogen separates trimethylgallium gas 108 and binds to activated gallium, and n-type dopant Si is doped and activated by silane gas (SiH ₄ ). An n-GaN contact layer 117 is grown.

In the formation of the n-GaN contact layer 117 shown in FIG. 2, when ammonia is used as a nitrogen supply source, the reaction formula is Ga (CH ₃ ) ₃ + 3NH ₃ → GaN + N (CH ₃ ) ₂ + NH (CH ₃ ) + 4H ₂ → GaN + N ₂ + a _{C 2 H 6 + CH 4 +} 4H 2. When trimethylamine N (CH ₃ ) ₃ is used as the nitrogen supply source, the reaction formula is Ga (CH ₃ ) ₃ + N (CH ₃ ) ₃ → GaN + 3C ₂ H ₆ . In order to obtain the same nitrogen as that of ammonia, the amount of gas may be 1/3. However, since the reaction is slower than that of ammonia, there is a drawback that the conventional horizontal high flow rate vapor phase growth apparatus cannot be used.

FIG. 1 shows an improved vapor phase growth apparatus 92. Since trimethylamine has fewer by-products than the above reaction formula compared with ammonia, solid substances are formed on the wall of the reaction furnace 100 facing the substrate 101 after vapor phase growth. It was investigated whether there was adhesion and dirt. As a result, there was no solid matter adhesion and dirt. The obtained n-GaN contact layer 117 has a thickness of 4.0 μm ± 2%, a mobility of 800 cm ² / V · S, a carrier concentration of 1 × 10 ¹⁷ / cm ³ to 1 × 10 ¹⁹ / cm ^3, which depends on ammonia. The same good results as growth were obtained.

Next, the vapor phase growth method according to the best mode 2 for carrying out the present invention will be described with reference to FIGS. FIG. 3 is a schematic diagram of an n-cladding layer. In FIG. 1, carrier gas, hydrogen gas 3.5 L / min from the introduction part 104 of the first type gas 10, and trimethylgallium (TMG) Ga (CH ₃ ) ₃ as 27 μ-mol / min as the first type gas 108. , Trimethylaluminum (TMA) Al (CH ₃ ) ₃ is supplied at 3 μ-mol / min and silane gas (SiH ₄ ) having a concentration of 1 ppm diluted with hydrogen to dope Si as an n-type dopant.

While supplying the above, the substrate 101 is heated to 550 ° C. by the heater 103 while supplying trimethylamine N (CH ₃ ) ₃ at 0.1 mol / min and nitrogen gas 3.5 L / min as the second kind gas 109. Then, the light from the infrared light source 115 is reflected by the reflecting plate 116 on the substrate surface of the n-GaN substrate 101. Then, the surface of the substrate 101 was further heated to 450 ° C., and a 0.5 μm n-Ga _0.9 Al _0.1 N clad layer 118 (shown in FIG. 3) was formed at 1000 ° C.

  Since the reaction of trimethylamine is slower than that of ammonia, the substrate 101 is heated in advance to 550 ° C. by the heater 103, and the flow rate control of the trimethylamine gas of the second kind gas 109 (reacted gas) is provided below the opening 111 of the reaction furnace 100 of FIG. The flow rate of the discharge portion 107 was reduced).

  Thus, a protruding portion 112 of the trimethylamine gas 109 is formed, a side pressure 109A is applied to the trimethylgallium gas and the trimethylaluminum gas 8 of the first type gas 108, and the trimethylamine gas of the second type gas 109 and the trimethyl of the first type gas 108 are added. Gallium gas is pressed against the n-GaN substrate 101.

  Therefore, the trimethylamine gas of the second type gas 109 and the trimethylgallium gas of the first type gas 108 are heated to 1000 ° C. when they contact the surface of the substrate 101, so that thermal convection is suppressed.

Since the grown n-Ga _0.9 Al _0.1 N cladding layer 118 is covered with the trimethylamine gas 109, re-decomposition of aluminum and nitrogen can be suppressed. More specifically, since the substrate 101 is heated to 550 ° C. by the heater 103 in advance, the surface of the substrate 101 is redened at the moment when the trimethylgallium gas, the trimethylaluminum gas 108 and the trimethylamine gas 109 touch the surface of the substrate 101. Since the light from the external light source 115 is reflected by the reflecting plate 116 and the surface of the substrate 101 is further heated at 450 ° C., crystal growth proceeds on the surface of the substrate 101 at a growth temperature of 1000 ° C.

At a growth temperature of 1000 ° C., trimethylamine 109 is decomposed, and active nitrogen is separated from trimethylgallium gas and trimethylaluminum gas 108 and combined with activated gallium and active aluminum. Further, the n-type dopant Si is doped and activated by silane gas (SiH ₄ ), and the n-Ga _0.9 Al _0.1 N cladding layer 118 grows.

In the formation of the n-Ga _0.9 Al _0.1 N cladding layer 118 shown in FIG. 3, conventionally, ammonia as a nitrogen supply source and aluminum as a group III material react strongly with each other in the gas phase to add an alkyl compound. Was making. Polymerization inhibited the growth of the GaAlN cladding layer.

However, in the vapor phase growth method using the vapor phase growth apparatus 92 of FIG. 1, since ammonia is not used, the above inhibition is eliminated. The reaction formula is Al (CH ₃ ) ₃ + 3NH ₃ → AlN + N (CH ₃ ) ₂ + NH (CH ₃ ) + 4H ₂ → InN + N ₂ + C ₂ H ₆ + CH ₄ + 4H ₂ . When trimethylamine N (CH ₃ ) ₃ is used as the nitrogen supply source, the reaction formula is Al (CH ₃ ) ₃ + N (CH ₃ ) ₃ → AlN + 3C ₂ H ₆ . In order to obtain the same nitrogen as ammonia, the gas amount may be 1/3. However, since the reaction is slower than that of ammonia, the conventional horizontal high flow rate vapor phase growth apparatus cannot be used.

FIG. 1 shows a vapor phase growth apparatus 92 improved from this. That is, trimethylamine has fewer by-products than the above reaction formula compared to ammonia, and therefore, after vapor phase growth, it was investigated whether there was solid matter adhesion or contamination on the wall of the reaction furnace 100 facing the substrate 101. As a result, there was no solid matter adhesion and dirt. The film thickness of the obtained n-Ga _0.9 Al _0.1 N cladding layer 118 is 0.5 μm ± 2%, and the carrier concentration is 1 × 10 ¹⁹ / cm ^3. The same good results were obtained.

Next, a vapor phase growth method according to the best mode 3 for carrying out the present invention will be described with reference to FIGS. FIG. 4 is a schematic view of the light emitting layer. In FIG. 1, after setting the n-GaN substrate 101 on the susceptor 102, the inside of the reaction furnace 100 is replaced with hydrogen gas. After that, from the introduction part 104 of the first type gas 108, hydrogen gas 3.5L / min and trimethyl gallium (TMG) Ga (CH ₃ ) ₃ as the first type gas 108 are 20.5 μ-mol / min and trimethyl. Indium (TMI) In (CH ₃ ) ₃ is supplied at 9.5 μ-mol / min. While supplying the above, as the second type gas 109, trimethylamine N (CH ₃ ) ₃ was supplied at 2.1 mol / min and nitrogen gas 3.5 L / min, and the substrate 101 was heated to 500 ° C. by the heater 103. Heat to.

Then, light from the infrared light source 115 is reflected by the reflector 116 on the surface of the n-GaN substrate 101, the surface of the substrate 101 is further heated at 300 ° C., and 50 nm In _0.2 Ga at 800 ° C. _{A 0.8} N blue light emitting layer 119 was formed.

  Since the reaction of trimethylamine is slower than that of ammonia, the substrate 101 is heated to 500 ° C. by the heater 103 in advance, and the flow rate control of the trimethylamine gas of the second kind gas 109 is performed under the opening 111 of the reaction furnace 100 in FIG. The flow rate of the gas discharge unit 107 is reduced).

  Thereby, a protruding portion 112 of the trimethylamine gas 109 is formed, and a side pressure 109A is applied to the trimethylgallium gas of the first kind gas 108. The trimethylamine gas of the second kind gas 109 and the trimethylgallium gas 108 of the first kind gas 108 are pressed against the n-GaN substrate 101.

  Therefore, when a side pressure 109A is applied to the trimethylgallium gas of the first type gas 108 and the trimethylamine gas of the second type gas 109 comes into contact with the surface of the substrate 101, it is heated to 800 ° C., so that thermal convection is suppressed.

Since the grown In _0.2 Ga _0.8 N blue light-emitting layer 119 is covered with the trimethylamine gas 109, re-decomposition of indium and nitrogen can be suppressed. More specifically, the substrate 101 is preheated to 500 ° C. by the heater 103. Therefore, at the moment when trimethylgallium gas, trimethylindium 108, and trimethylamine gas 109 touch the surface of the substrate 101, the light from the infrared light source 115 is reflected by the reflecting plate 116 and further heated at 300 ° C. Therefore, crystal growth of the In _0.2 Ga _0.8 N light emitting layer 119 proceeds at a growth temperature of 800 ° C.

At a growth temperature of 800 ° C., trimethylindium gas, trimethylgallium gas 108 and trimethylamine gas 109 decompose, and active indium and active nitrogen decompose trimethylindium gas and trimethylgallium gas 108 and combine with active gallium. The In _0.2 Ga _0.8 N blue light emitting layer 119 is grown.

In the formation of the In _0.2 Ga _0.8 N blue light-emitting layer 119 shown in FIG. 4, when ammonia is used as a nitrogen supply source, the reaction formula is In (CH ₃ ) ₃ + 3NH ₃ → InN + N (CH ₃ ) ₂ + NH ( CH ₃₎ + 4H ₂ → the _{InN + N 2 + C 2 H} 6 + CH 4 + 4H 2.

When trimethylamine N (CH ₃ ) ₃ is used as a nitrogen source, the reaction formula is In (CH ₃ ) ₃ + N (CH ₃ ) ₃ → InN + 3C ₂ H ₆ . In order to obtain the same nitrogen as ammonia, the gas amount may be 1/3. However, since the reaction is slower than that of ammonia, the conventional horizontal high flow rate vapor phase growth apparatus cannot be used.

  FIG. 1 shows an improved vapor phase growth apparatus 92. Since trimethylamine has fewer by-products than the above reaction formula compared to ammonia, solid phase is formed on the wall of the reactor 100 facing the substrate 101 after vapor phase growth. It was investigated whether there was adhesion and dirt. As a result, there was no solid matter adhesion and dirt. The obtained InGaN light-emitting layer 119 had a film thickness of 50 nm ± 2%, a band gap of 2.9 eV, and a wavelength of 430 nm, and the same light output as that of growth by ammonia could be obtained.

Next, a vapor phase growth method according to the best mode 4 for carrying out the present invention will be described with reference to FIGS. FIG. 5 is a schematic view of a p-cladding layer. In FIG. 1, from the introduction part 104 of the first type gas 108, hydrogen gas 3.5 L / min as a carrier gas and trimethylgallium (TMG) Ga (CH ₃ ) ₃ as the first type gas 108 are 27 μ-mol / Min and trimethylaluminum (TMA) Al (CH ₃ ) ₃ are introduced by 3 μ-mol / min.

Then, in order to dope p-type dopant Mg, trimethylamine N (CH ₃ ) ₃ as the second kind gas 109 is 0.1 mol / w while supplying bismicropenta-genylmagnesium (Cp ₂ Mg). min and nitrogen gas 3.5 L / min are supplied.

However, the substrate 101 is heated to 550 ° C. by the heater 103, the light from the infrared light source 115 is reflected by the reflector 116 on the substrate surface of the n-GaN substrate 101, and the surface of the substrate 101 is further heated by 450 ° C. Is done. A p-Ga _0.9 Al _0.1 N cladding layer 120 of 0.5 μm was formed at 1000 ° C.

  Since the reaction of trimethylamine is slower than that of ammonia, the substrate 101 is heated in advance to 550 ° C. by the heater 103, and the flow rate control of the trimethylamine gas of the second kind gas 109 (reacted gas) is provided below the opening 111 of the reaction furnace 100 of FIG. The flow rate of the discharge unit 107 is reduced).

  Thereby, the protrusion 112 of the trimethylamine gas 109 is formed, and a side pressure 109A is applied to the trimethylgallium gas and the trimethylaluminum gas of the first kind gas 108. The trimethylamine gas of the second kind gas 109 and the trimethylgallium gas 108 of the first kind gas 108 are pressed against the n-GaN substrate 101. Therefore, since the trimethylamine gas of the second kind gas 19 and the trimethylgallium gas of the first kind gas 108 are heated to 1000 ° C. when contacting the substrate surface, thermal convection is suppressed.

Since the grown p-Ga _0.9 Al _0.1 N cladding layer 120 is covered with the trimethylamine gas 109, re-decomposition of aluminum and nitrogen can be suppressed. More specifically, the substrate 101 is preheated to 550 ° C. by the heater 103. Therefore, the light from the infrared light source 115 is reflected by the reflecting plate 116 at the moment when the trimethylgallium gas, the trimethylaluminum gas 108, and the trimethylamine gas 109 touch the surface of the substrate 101, and is heated further by 450 ° C. Crystal growth proceeds at a growth temperature of 1000 ° C.

At a growth temperature of 1000 ° C., trimethylamine 109 is decomposed, and active nitrogen is separated from trimethylgallium gas and trimethylaluminum gas 108 and combined with activated gallium and active aluminum. Further, p-type dopant Mg is doped and activated by bismicropenta-genylmagnesium (Cp ₂ Mg) to form a p-Ga _0.9 Al _0.1 N cladding layer 120 on the light emitting layer 119. did.

In the formation of the p-Ga _0.9 Al _0.1 N clad layer 120 shown in FIG. 5, conventionally, ammonia, which is a nitrogen supply source, and aluminum, which is a group III material, react strongly in the gas phase to add an alkyl compound. I was making a compound. Although the polymerization has inhibited the growth of GaAlN, in the vapor phase growth apparatus 92 of FIG. 1 and the vapor phase growth method of the present invention, ammonia is not used, so the above inhibition is eliminated.

The reaction formula is Al (CH ₃ ) ₃ + 3NH ₃ → AlN + N (CH ₃ ) ₂ + NH (CH ₃ ) + 4H ₂ → AlN + N ₂ + C ₂ H ₆ + CH ₄ + 4H ₂ . When trimethylamine N (CH ₃ ) ₃ is used as the nitrogen source, the reaction formula is Al (CH ₃ ) ₃ + N (CH ₃ ) ₃ → AlN + 3C ₂ H ₆ . In order to obtain the same nitrogen as ammonia, the gas amount may be 1/3.

However, since the reaction is slower than that of ammonia, the conventional horizontal high flow rate vapor phase growth apparatus cannot be used. FIG. 1 shows an improved vapor phase growth apparatus 92. Since trimethylamine has fewer by-products than the above reaction formula compared with ammonia, solid matter adheres to the reaction furnace 100 wall facing the substrate 101 after vapor phase growth. , And investigated for dirt. As a result, there was no solid matter adhesion and dirt. The obtained p-Ga _0.9 Al _0.1 N clad layer 120 has a thickness of 0.5 μm ± 2% and a carrier concentration of 3 × 10 ¹⁸ / cm ^3, which is the same as when ammonia is used. Good results were obtained.

Next, the vapor phase growth method according to the best mode 5 for carrying out the present invention will be described with reference to FIGS. FIG. 6 is a schematic diagram of the p-contact layer and the p electrode. In FIG. 1, from the introduction part 104 of the first type gas 108, nitrogen gas 3.5 L / min as a carrier gas and trimethyl gallium (TMG) Ga (CH ₃ ) ₃ as 30 μ-mol as the first type gas 108 are obtained. Only / min is introduced.

Nitrogen trimethylamine N (CH ₃ ) ₃ is 0.1 mol / min as the second kind gas 109 while supplying bismicropenta-genylmagnesium (Cp ₂ Mg) for doping Mg as a p-type dopant, and nitrogen. While supplying the gas at 3.5 L / min, the n-GaN substrate 101 is heated to 550 ° C. by the heater 103.

  Then, the substrate surface of the n-GaN substrate 101 is reflected from the light from the infrared light source 115 by the reflector 116, the surface of the substrate 101 is further heated at 450 ° C., and 0.1 μm p− at 1000 ° C. A GaN contact layer 121 was formed.

  Since the reaction of trimethylamine is slower than that of ammonia, the substrate 101 is preheated to 550 ° C. by the heater 103. Control of the flow rate of the trimethylamine gas of the second type gas 109 (such as reducing the flow rate of the exhausted portion 107 of the reacted gas) is performed below the opening 111 of the reaction furnace 100 of FIG.

  Thereby, the protruding portion 112 of the trimethylamine gas 109 is formed, and a side pressure 109A is applied to the trimethylgallium gas of the first kind gas 108. The trimethylamine gas of the second kind gas 109 and the trimethylgallium gas of the first kind gas 108 are pressed against the n-GaN substrate 101. Therefore, the trimethylamine gas of the second type gas 109 and the trimethylgallium gas of the first type gas 108 are heated to 1000 ° C. when they come into contact with the surface of the substrate 101, so that thermal convection is suppressed.

  Since the grown p-GaN contact layer 121 is covered with the trimethylamine gas 109, re-decomposition of nitrogen is suppressed. More specifically, the substrate 101 is preheated to 550 ° C. by the heater 103. Therefore, as soon as the trimethylgallium gas 108 and the trimethylamine gas 109 touch the surface of the substrate 101, the light from the infrared light source 115 is reflected by the reflecting plate 116 and is further heated at 450 ° C. Crystal growth proceeds depending on the growth temperature.

At a growth temperature of 1000 ° C., trimethylamine 109 is decomposed and active nitrogen is separated, and trimethylgallium gas 108 is separated and bonded to activated gallium. Furthermore, p-type dopant Mg is doped and activated by bismicropenta-genyl magnesium (Cp ₂ Mg), and the p-GaN contact layer 121 grows.

  As in FIG. 2, the gas amount of trimethylamine may be 1/3 compared to ammonia, but the conventional horizontal type high flow rate vapor phase growth apparatus cannot be used because the reaction is slower than ammonia. FIG. 1 shows a vapor phase growth apparatus 92 improved from this. Since trimethylamine has fewer by-products than the above reaction formula compared to ammonia, after vapor phase growth, the wall of the reaction furnace 100 facing the substrate 101 was examined for solid adhesion and contamination.

As a result, there was no solid matter adhesion and contamination. The thickness of the obtained p-GaN film was reduced to 0.1 μm ± 2%, the hole concentration was 6 × 10 ¹⁸ cm ⁻³ , and the resistance value in the p region was 0.3 Ω · cm. Further, nickel and gold were deposited on the p-GaN contact layer 121 as the p-electrode 122. After that, when the contact resistance between the p-GaN contact layer 121 and the p-electrode 122 was measured, it can be reduced to 10 ⁻³ to 10 ⁻⁴ Ω · cm as in the case of using ammonia. It was.

  Next, the features of Embodiments 1 to 5 are summarized below. In the vapor phase growth method of the present invention, a susceptor 102 for placing the substrate 101 and a heater 103 for heating the susceptor 102 are provided. The temperature of the susceptor 102 is T1, and vapor growth is performed at a temperature of T1 + T2 by further T2 heating by the heating means on the surface of the substrate 101.

An introduction part 104 and exhaust parts 105 and 113 for the first type gas 108 are provided in the lower part inside the reaction furnace 100, and an introduction part 106 and an exhaust part 107 for the second kind gas 109 are provided in the upper part. An organic group III metal is used as the first type gas 108, a nitride-containing hydrocarbon is used as the second type gas 109, the first type gas 108 is pressed against the surface of the substrate 101 by the side pressure 109A of the second type gas, and the T1 + T2 Vapor phase growth at a temperature of
Further, n-layer region gallium nitride compound semiconductors 117 and 118 were formed at the temperature of T1 + T2.
Then, the p-layer region gallium nitride compound semiconductors 120 and 121 were formed at the temperature of T1 + T2.
In addition, the light emitting layer region gallium nitride compound semiconductor 119 was formed at the temperature of T1 + T2.
The n-layer region 117, 118 is composed of a multilayer film composed of an n-type GaN layer and an n-type Ga _1-b Al _b N layer (where 0 ≦ b ≦ 1).
The p-layer regions 120 and 121 are each composed of a multilayer film composed of a p-type GaN layer and a p-type Ga _1-b Al _b N layer (where 0 ≦ b ≦ 1).
The light emitting layer region 119 is composed of a film made of an In _b Ga _1-b N layer (where 0 ≦ b ≦ 1).

  In addition, this invention is not limited to the said best form 1-5, A various deformation | transformation is possible based on the meaning of this invention, and they are not excluded from the scope of the present invention. . For example, in the above embodiment of the present invention, a semiconductor vapor phase growth method using an n-GaN substrate has been described. However, other substrates such as a sapphire substrate, a SiC substrate, a Si substrate, a GaAs substrate, a GaP substrate, an InP substrate, etc. The substrate can be appropriately selected in consideration of the matching between lattices, thermal expansion, and the like.

  Furthermore, the vapor phase growth method using a GaN-based compound semiconductor has been described. However, since ammonia is not used as a nitrogen supply source, one or all of N of other semiconductor materials such as InGaAlN are replaced with As and / or P. The present invention can also be applied to a vapor phase growth method using such a material or a GaAs compound semiconductor.

  Also, a vapor phase growth apparatus that does not use ammonia as a nitrogen supply source and a vapor phase growth method have been described. Even when ammonia is used because infrared light is used for heating the substrate surface from outside the reactor. Applicable. Further, ammonia and materials other than ammonia may be used in combination as the nitrogen supply source in accordance with the characteristics of the growth film.

  Further, in the best modes 1 to 5 of the present invention, the vapor phase growth method using one n-GaN substrate has been described. However, a plurality of substrates are placed on a susceptor, and the substrate itself rotates. Further, by the revolution of the susceptor, a vapor phase growth apparatus and a vapor phase growth method with high productivity can be realized.

  Further, the temperatures of T1 and T2 can be appropriately selected according to the growth film.

  Furthermore, although the example which mixed the gas which does not contain source gas and source gas as 1st type gas A and 2nd type gas B was shown, the gas which does not contain source gas and source gas is suitably selected according to a growth film. be able to.

  Moreover, although the example applied to manufacture of a GaN-type semiconductor light-emitting device was shown as an example using a GaN-type compound semiconductor, it is applicable also to manufacture of GaN-type electron transit devices, such as a GaN-type field effect transistor (FET). .

  Further, an example in which quartz is used as a reaction furnace has been shown, but quartz glass or quartz sintered body can also be used.

  In addition, as long as the nitrogen source does not generate hydrogen during active nitrogen decomposition, such as ammonia, select from trimethylamine, trimethylamine added to trimethylamine described in Forms 1 to 5, trihylazine, etc. Can do.

It is the schematic of the vapor phase growth apparatus 92 concerning the best form for implementing this invention. It is the schematic of the n-contact layer for demonstrating the vapor phase growth method which concerns on the best form 1 for implementing this invention. It is the schematic of the n-cladding layer for demonstrating the vapor phase growth method which concerns on the best form 2 for implementing this invention. It is the schematic of the light emitting layer for demonstrating the vapor phase growth method which concerns on the best form 3 for implementing this invention. It is the schematic of the p-cladding layer for demonstrating the vapor phase growth method which concerns on the best form 4 for implementing this invention. It is the schematic of the p-contact layer and p electrode for demonstrating the vapor phase growth method which concerns on the best form 5 for implementing this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Reaction furnace 101 Substrate 102 Susceptor 103 Heater 104 First type gas introduction part 105 Reacted gas discharge part 106 Second type gas introduction part 107 Reacted gas discharge part 108 First kind gas 109 Second kind gas 110 Partition part 111 Opening part 112 Projection part of second type gas

Claims (14)

In a vapor phase growth apparatus having a susceptor for placing a substrate and a heater for heating the susceptor, the temperature of the susceptor is set to T1, and further T2 is heated by the heating means on the surface of the substrate, so that the temperature becomes T1 + T2. A vapor phase growth apparatus characterized by performing vapor phase growth. In a vapor phase growth apparatus having a susceptor for placing a substrate and a heater for heating the susceptor, the temperature of the susceptor is set to T3, and the temperature of the substrate surface is further heated by T4 irradiation by infrared light irradiation from above the susceptor. A vapor phase growth apparatus characterized by performing vapor phase growth at a temperature of T3 + T4. A susceptor for placing the substrate, a heater for heating the susceptor, and a substrate disposed inside the reaction tube so as to be substantially parallel to the substrate. A partition portion having an introduction portion and a discharge portion for the second type gas at the upper portion, and an opening portion located above the substrate is provided in the partition portion, and the reaction tube located above the opening portion is provided. A vapor phase growth apparatus provided with a substrate surface heating means outside. A susceptor for placing the substrate, a heater for heating the susceptor, and a substrate disposed inside the reaction tube so as to be substantially parallel to the substrate. A partition portion having an introduction portion and a discharge portion for the second type gas at the upper portion, wherein the partition portion is provided with an opening portion located above the substrate, and the reaction tube located above the opening portion. A vapor phase growth apparatus provided with an infrared light source for heating the substrate surface outside. The growth gas 1 is used as the first type gas, the growth gas 2 is used as the second type gas, and the growth gas 1 is pressed against the surface of the substrate by the lateral pressure of the growth gas 2 to grow. The vapor phase growth apparatus according to claim 3 or 4. An organic group III metal is used as the first type gas, a nitride-containing hydrocarbon is used as the second type gas, and the first type gas is pressed against the surface of the substrate by the lateral pressure of the second type gas to grow. The vapor phase growth apparatus according to claim 3 or 4, wherein the vapor phase growth apparatus is characterized. There is a susceptor for placing a substrate and a heater for heating the susceptor. The temperature of the susceptor is T1, and further T2 heating is performed by a heating means on the substrate surface, thereby vapor phase growth at a temperature of T1 + T2. A vapor phase growth method characterized by the above. The lower part of the reaction tube has a first-type gas introduction part and a discharge part, and the upper part has a second-type gas introduction part and a discharge part, and an organic group III metal is used as the first-type gas, A nitride-containing hydrocarbon is used as the second type gas, and the first type gas is pressed against the surface of the substrate by a side pressure of the second type gas, and vapor phase growth is performed at a temperature of T1 + T2. Item 8. The vapor phase growth method according to Item 7. 9. The vapor phase growth method according to claim 8, wherein an n-layer region gallium nitride compound semiconductor is formed at a temperature of T1 + T2. 9. The vapor phase growth method according to claim 8, wherein a p-layer region gallium nitride compound semiconductor is formed at a temperature of T1 + T2. 9. The vapor phase growth method according to claim 8, wherein a light emitting layer region gallium nitride compound semiconductor is formed at a temperature of T1 + T2. 10. The gas phase according to claim 9, wherein the n-layer region is formed of a multilayer film including an n-type GaN layer and an n-type Ga _1-b Al _b N layer (where 0 ≦ b ≦ 1). Growth method. 11. The gas phase according to claim 10, wherein the p-layer region is formed of a multilayer film including a p-type GaN layer and a p-type Ga _1-b Al _b N layer (where 0 ≦ b ≦ 1). Growth method. 12. The vapor phase growth method according to claim 11, wherein the light emitting layer region is composed of a film composed of an In _b Ga _1-b N layer (where 0 ≦ b ≦ 1).

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