JPH11329981A - Method and system for epitaxially growing thin film of nitride semiconductor and nitride semiconductor light emitting element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent hydrogen, causing drop in In intake rate, from being fed onto a substrate by providing a piping for supplying group V material to a reaction furnace with a unit for decomposing group V material and a unit for adsorbing decomposed hydrogen through a hydrogen occlusion alloy in front of the reaction furnace. SOLUTION: A group V material, i.e., NH3 , fed from a supply line 1 is thermally decomposed by means of a heater 8 and decomposed gas is introduced to a hydrogen adsorbing unit 9 encapsulating a hydrogen occulusion alloy. On the other hand, NH3 introduced from the line 1 and decomposed by the heater 8 is fed to a hydrogen removing unit 9 and only hydrogen is discharged through a hydrogen transmitting Pd alloy film. At the time of growing InGaN, NH3 is thermally decomposed by the decomposition heater 8 and introduced to the hydrogen removing unit 9 before being fed to a reaction furnace thus preventing hydrogen, causing drop in In intake rate, from being fed onto a substrate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nitride semiconductor thin film crystal growth apparatus, a growth method, and a light emitting device manufactured using the growth apparatus.

[0002]

2. Description of the Related Art A semiconductor crystal having a composition of InAlGaN is used as a material for a light emitting diode emitting ultraviolet or blue light and a semiconductor laser. In _x Ga _1-x N, (0 ≦ x ≦ 1) is used for the active layer of these light emitting elements. This In _x Ga _1-x N can change the band gap from 1.9 eV to 3.4 eV by changing the composition of In (ie, x), and emits light in a wide range from red light to ultraviolet light. It is a semiconductor material that can be used.

FIG. 8 shows an example of a light emitting device of an InAlGaN semiconductor crystal. Here, 21 is a sapphire substrate, 22 is an AlN buffer layer, 23 is a Si-doped n-type GaN clad layer, 24 is an InGaN active layer, and 25 is Mg-doped p.
A type AlGaN protective layer, 26 is a Mg-doped p-type GaN cladding layer, 27 is an n-type electrode, 28 is a p-type transparent electrode, and 29 is a p-type electrode.

[0004] Conventionally, such a light-emitting element such as InAlG
The aN-based semiconductor crystal is formed by metal organic chemical growth (hereinafter referred to as MOCV).
D method). FIG. 7 shows an example of the growth apparatus. In FIG. 7, reference numeral 1 denotes a line for supplying a group V material NH ₃ . 2 is a group III material TMG (trimethylgallium), TMA (trimethylaluminum), TMI (trimethylindium) and a p-type impurity material Cp ₂ Mg
A line for supplying an organic metal material such as (cyclopentadienylmagnesium) and SiH ₄ as an n-type impurity material. 3 is an N ₂ supply line for adjusting the mixing degree of each raw material.
4 is a reaction furnace, 5 is a susceptor, 6 is a sapphire substrate, 7
Is a work coil for high frequency heating. In such a growth apparatus, each raw material is decomposed by the heat of the sapphire substrate in the reaction furnace, and a nitride semiconductor crystal grows on the sapphire substrate.

When the light-emitting device structure shown in FIG. 8 is grown by MOCVD using a conventional growth apparatus, when growing a layer other than the InGaN active layer, H ₂ is used as a carrier gas and necessary materials are placed in a reactor. Each of the raw materials is decomposed by the heat of the introduced substrate, and respective layers of an AlN buffer layer, a Si-doped n-type GaN layer, a Mg-doped p-type AlGaN protective layer, and a Mg-doped p-type GaN layer are grown.

On the other hand, when growing an InGaN active layer, necessary materials are introduced into a reaction furnace using N ₂ as a carrier gas as disclosed in Japanese Patent Application Laid-Open No. Is decomposed to grow an InGaN active layer. This is because, when the growth of the InGaN layer and of H ₂ to grow as a carrier gas InG
This is because InN in aN is decomposed and desorbed from the crystal lattice, so that the efficiency of taking In into the film is reduced.

Further, Mg-doped A immediately after MOCVD growth is used.
The lGaN layer and the Mg-doped GaN layer exhibit high resistance because hydrogen generated by the decomposition of NH ₃ is taken into the film and combined with the Mg dopant to inactivate Mg.
A Mg-doped AlGaN layer exhibiting high resistance immediately after this growth,
To lower the resistance value of the Mg-doped GaN layer and make it p-type,
As disclosed in JP-A-8-213656, it is necessary to perform annealing at 800 ° C. in an N ₂ atmosphere for about 20 minutes. By this annealing, 2 × 10 ¹⁷ / cm
A p-type carrier concentration of ³ is obtained. After that, an n-type electrode and a p-type electrode are formed to produce a light emitting device as shown in FIG.

On the other hand, Japanese Patent Application Laid-Open No. Hei 10-41544 discloses a means for removing hydrogen which is a factor for inactivating a p-type dopant. The hydrogen removing means will be described with reference to FIG. In FIG. 9, reference numeral 1 denotes a line for supplying a group V material NH ₃ . 2 is a group III material TMG (trimethylgallium), TMA (trimethylaluminum), TMI (trimethylindium) and a p-type impurity material Cp ₂ Mg
A line for supplying an organic metal material such as (cyclopentadienylmagnesium) and SiH ₄ as an n-type impurity material. 4 is a reaction furnace, 5 is a susceptor, 6 is a sapphire substrate, 7 is a high-frequency work coil for heating the substrate, 8 is an NH ₃ decomposition device, 9
Is a hydrogen storage part, 30 is a hydrogen storage alloy such as palladium, 3
1 NH ₃ heating body for decomposition, 32 NH ₃ decomposing heating body 3
1 is a high-frequency work coil for heating 1. This prior art kept heated the NH ₃ decomposing heating member 31 of the NH ₃ decomposing device 8 to 900 ° C. to 1200 ° C., after heating decompose NH ₃ in the decomposition apparatus 8 is guided to the hydrogen storage unit 9, The hydrogen generated by decomposition of NH ₃ in the hydrogen storage alloy 30 in the hydrogen storage unit 9 is stored and removed, and then supplied to the growth apparatus.

[0009]

The efficiency of capturing In of the InGaN layer is greatly affected by the hydrogen present in the growth atmosphere, and the efficiency of capturing In is reduced even by a slight amount of hydrogen. This is why N ₂ is used as a carrier gas when growing the InGaN active layer. However, when NH ₃ used as a group V material is thermally decomposed by the heat of the substrate, hydrogen is generated. Hydrogen generated by the thermal decomposition of NH ₃ reduces the efficiency of taking In into the film, and there is a problem that a large amount of TMI must be supplied to increase the In composition.

Further, the passivation of Mg as a p-type dopant is caused by hydrogen generated by thermal decomposition of NH _{3 as} a group V raw material, combined with Mg. In order to desorb hydrogen bonded to Mg, which is a deactivating factor, from the film and activate Mg, M
After OVCVD growth, it was necessary to perform annealing in a nitrogen atmosphere. Further, even if annealing is performed in a nitrogen atmosphere for the purpose of activating Mg, hydrogen completely bonded to Mg cannot be eliminated from the film, so that 2 × 10 ¹⁷ / cm ³
As described above, there is a problem that the p-type carrier concentration does not increase. In addition, since annealing is performed at a high temperature of 800 ° C. after fabrication of the device structure, thermal damage is caused to the InGaN active layer, and diffusion of In and dopant occurs to deteriorate the light emitting characteristics of the device.

As described above, it has been a problem that hydrogen generated by decomposition of the group V raw material is taken into the crystal.

As a means for removing hydrogen generated by the decomposition of NH ₃ , a growth apparatus as shown in FIG. 9 has been devised. However, in the configuration of FIG. 9, since the high-temperature gas obtained by thermal decomposition of NH ₃ touches the hydrogen storage alloy, the temperature of the hydrogen storage alloy increases during the growth of the nitride semiconductor thin film crystal, and the hydrogen adsorption capacity decreases, As a result, it was found that the initial purpose of hydrogen storage and removal of hydrogen by the hydrogen storage alloy cannot be achieved. Accordingly, the nitride semiconductor crystal manufactured by the apparatus shown in FIG. 9 has an improved incorporation rate of In and a higher M than that of the conventional apparatus and method (when no hydrogen storage alloy is used).
No increase in the carrier concentration in the g-doped layer was observed, and as a result, high-temperature annealing after device fabrication as in the conventional case was necessary.

[0013]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, an MOCVD apparatus of the present invention comprises an apparatus for decomposing a group V raw material before a pipe for supplying a group V raw material to the reaction furnace. It is characterized by having a device for adsorbing and removing generated hydrogen with a hydrogen storage alloy, or a device for permeating and removing only hydrogen through a permeable membrane using a hydrogen permeable membrane.

After decomposing the group V raw material by a decomposing device provided in front of the reaction furnace, and bringing the raw material into contact with the hydrogen storage alloy, the hydrogen generated by the decomposition of the group V raw material is adsorbed and removed by the hydrogen storage alloy. . Alternatively, after decomposing the group V raw material by the decomposition apparatus, the hydrogen is permeable to the hydrogen permeable membrane by contacting the hydrogen permeable membrane with the hydrogen permeable membrane.

Therefore, when growing InGaN, Mg-doped G
During the growth of aN, the group V raw material is supplied into the reaction furnace through the decomposition device and the device for removing decomposition product hydrogen, thereby reducing the incorporation rate of In in the InGaN growth film and the p-type dopant Mg. Hydrogen which is an activation factor is not supplied onto the substrate.

Further, in the present invention, a heating mechanism is provided for cooling the hydrogen storage alloy to efficiently exhibit the hydrogen adsorption ability and for releasing the adsorbed hydrogen, so that the hydrogen adsorption ability can be regenerated and activated. .

[0017]

Embodiments of the present invention will be described below in detail with reference to the drawings. (Embodiment 1) A first embodiment will be described with reference to FIGS. 1, 2 and 3. FIG. FIG. 1 shows an example of a MOCVD apparatus according to an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a line for supplying NH ₃ as a group V raw material, 2 denotes a group III raw material such as TMG (trimethylgallium), TMA (trimethylaluminum), TMI (trimethylindium) and a p-type impurity raw material Cp ₂ Mg.
A line for supplying an organic metal material such as (cyclopentadienylmagnesium) and SiH ₄ as an n-type impurity material, 3 a N ₂ supply line for adjusting the mixing degree of each material,
4 is a reaction furnace, 5 is a susceptor, 6 is a sapphire substrate, 7
Is a work coil for high-frequency heating, 8 is a heater for decomposing NH ₃ , 9 is a hydrogen adsorption device, 10 is a bypass line, 11 is a switching valve, and 12 is an exhaust line of the hydrogen adsorption device. Although not shown in FIG. 1, a quartz flow channel is provided in the reaction furnace 4 for smooth gas flow.

NH ₃ supplied from line 1 is heated to about 1000 ° C. by a heater 8 to be decomposed. The decomposed gas is introduced into 9 hydrogen adsorption devices. A hydrogen storage alloy is sealed inside the hydrogen adsorption device 9.
The hydrogen adsorption device is cooled to 0 ° C. or lower, and is set so that hydrogen generated by decomposition of NH ₃ can be adsorbed to the hydrogen storage alloy efficiently. The length of the piping after the heater 8 is preferably as short as possible in order to suppress the recombination of the decomposed species. The heater 8, the hydrogen adsorption device 9, and the switching valve 11 are arranged immediately near the reaction furnace.

FIG. 2 shows a structural example of the hydrogen adsorption device 9. In FIG. 2, 11 is a switching valve, 12 is an exhaust line,
Reference numeral 13 denotes a plate-shaped hydrogen storage alloy made of, for example, CaNi ₅ . A plurality of plate-shaped hydrogen storage alloys are installed perpendicularly to the gas flow, so that hydrogen generated by decomposition can be efficiently removed. Numeral 14 is a cooling jacket for cooling the decomposition gas and cooling the hydrogen storage alloy. The cooling jacket circulates the liquid nitrogen and efficiently absorbs and removes hydrogen by cooling the decomposition gas and the hydrogen storage alloy. Reference numeral 15 denotes a heater for desorbing the stored hydrogen. When desorbing the hydrogen adsorbed on the hydrogen storage alloy, the refrigerant in the cooling jacket 14 is removed, and the switching valve 11 is operated while heating the hydrogen storage alloy with the heater 15 to operate the exhaust line 1.
If the inside of the hydrogen adsorbing device is evacuated to vacuum from 2, the adsorbed hydrogen is desorbed, and the hydrogen adsorbing ability of the hydrogen storage alloy can be easily recovered and activated. When CaNi ₅ is used as the hydrogen storage alloy, activation can be achieved by heating to 100 ° C.

FIG. 3 shows another example of the structure of the hydrogen adsorption device 9. In FIG. 3, reference numeral 11 denotes a switching valve, 12 denotes an exhaust line, 13 denotes a particulate hydrogen storage alloy, 14 denotes a cooling jacket, 15 denotes a heater for activation, and 16 denotes a filter having a finer grain than the granular hydrogen storage alloy. In the embodiment shown in FIG. 3, a granular hydrogen storage alloy is filled in a hydrogen adsorption device to increase the surface area of the hydrogen storage metal, so that the hydrogen generated by decomposition can be efficiently removed.

When a Ca-based alloy such as CaNi ₅ is used as the hydrogen storage alloy used in these hydrogen adsorption devices, the equilibrium hydrogen pressure is relatively low, and hydrogen can be efficiently adsorbed and removed. When heated to about ℃ and exhausted, the adsorbed hydrogen can be easily desorbed to activate the adsorption capacity, but there are many hydrogen storage alloys, and adsorption and desorption of Ti-Co system etc. are appropriate. C that occurs at temperature and pressure
Other than aNi ₅ can be used.

Next, AlInG using the growth apparatus of FIG.
A method for growing an aN-based light emitting device will be described. The structure of the element is the same as that of FIG. The heater 8 for decomposing NH _{3 in} FIG. 1 is heated to 1000 ° C., and the hydrogen adsorber 9 is made to flow liquid nitrogen through a cooling jacket and cooled to 77K.
The switching valve 11 allows NH ₃ to be supplied to the reaction furnace through the bypass line 10. In this state, the pressure of the reaction furnace is set to the atmospheric pressure, the sapphire substrate 21 is heated to 1100 ° C., and the substrate surface is cleaned for 20 minutes by flowing 20 l / min of hydrogen. Next, the substrate temperature was set to 550 ° C., H ₂ was used as a carrier gas, and 9 μmol / min of trimethylaluminum (TMA) was supplied from line 2 to NH 3.
₃ supplies A by supplying 3.5 l / min from the bypass line 10
The 1N buffer layer 22 is grown to 35 nm. Next, the substrate temperature was raised to 1050 ° C., and trimethylgallium (TM)
G) is supplied at 50 μmol / min and SiH ₄ at 10 nmol / min from the line 2, and NH ₃ is supplied at 7 l / min from the bypass line 10 to supply the n-type GaN cladding layer 23 at 4 μm.
grow up. After growing the n-type GaN cladding layer 23, the switching valve 11 is operated to make the NH ₃ decompose the heater 8,
It is set so as to be supplied to the reaction furnace through the hydrogen adsorption device 9. Next, the temperature of the substrate was lowered to 800 ° C., and 7.7 μmol / min of TMG, 3.4 μmol / min of trimethyl indium (TMI) and SiH were used with N ₂ as a carrier gas.
₄ at 3 nmol / min from line 2 and NH ₃ at 20 l /
The hydrogen is decomposed by a decomposition heater 8, and the hydrogen generated by decomposition is adsorbed and removed by a hydrogen adsorption device 9, and then supplied to a reaction furnace.
An n _0.3 Ga _0.7 N single quantum well active layer 24 is grown to a thickness of 2 nm. Next, 7.7 μmol / min of TMG and 00.
From 7 μmol / min and 0.2 μmol / min of dicyclopentadienyl magnesium (Cp ₂ Mg) from line 2, NH ₃ was decomposed at 20 l / min by a heater 8 for decomposition and generated by a hydrogen adsorption device 9. After the removed hydrogen is absorbed and removed, the resultant is supplied to a reaction furnace to grow a p-type Al _0.1 Ga _0.9 N protective layer 5 to a thickness of 20 nm. Next, the substrate temperature was raised to 1050 ° C., TMG was 50 μmol / min, and Cp ₂ Mg was 0.2 μm.
mol / min from the second line, NH ₃ is decomposed by a heater 8 for decomposing 7l / min, after adsorbing and removing the hydrogen produced decomposed by hydrogen adsorption unit 9, p-type GaN is supplied to the reactor
A cladding layer 25 is grown to a thickness of 300 nm. Next, a dry etching process is performed to partially expose the n-type GaN cladding layer 23, and a Ti / Al-n-type electrode 27, a Ni-p-type transparent electrode 28, and an Au-p-type electrode 29 are deposited and shown in FIG. A light-emitting element is manufactured.

When performing InGaN growth as described above,
NH_ThreeIs decomposed by heating with a decomposition heater 8, and then hydrogen
After being led to the adsorption device 9 to remove generated hydrogen, the reaction furnace
Hydrogen that lowers the incorporation rate of In by supplying
Since it is not supplied on the plate, the In
An InGaN crystal having a high composition ratio can be obtained. In addition, Mg
Of AlGaN and Mg-doped p-type GaN
Is also a factor in increasing the resistance of the film.
Activates Mg because no hydrogen is supplied on the substrate
There is no need to perform annealing. In this embodiment, annealing is performed.
1 × 10 ¹⁸/ Cm^ThreeShows above carrier concentration
p-type GaN can be obtained.

(Embodiment 2) Next, a second embodiment will be described with reference to FIGS. In FIG. 4, 1 is a line for supplying NH ₃ as a group V material, and 2 is a TM as a group III material.
A line for supplying an organic metal material such as G, TMA, TMI and SiH ₄ as an n-type impurity material and a Cp ₂ Mg as a p-type impurity material, 3 is an N ₂ supply line for adjusting the mixing degree of each material, 4 Is a reaction furnace, 5 is a susceptor, 6 is a sapphire substrate, 7 is a work coil for high frequency heating, 8 is a heater for decomposing NH ₃ , 9 is a hydrogen removing device,
Is a bypass line, 11 is a switching valve, and 12 is an exhaust line. Although not shown in FIG. 4, a quartz flow channel is provided in the reaction furnace 4 for smooth gas flow.

FIG. 5 shows an example of the structure of the hydrogen removing device 9. In FIG. 5, reference numeral 17 denotes a Pd-based alloy film having hydrogen permeability.
Reference numeral 18 denotes a heater for heating the Pd-based hydrogen-permeable alloy film, which heats the Pd-based hydrogen-permeable alloy film from 350 ° C. to 400 ° C. If one side of the hydrogen permeable Pd alloy film 17 is always kept under reduced pressure by the exhaust line 12, hydrogen existing in the hydrogen removing device 9 will be removed from the hydrogen permeable Pd alloy film 17.
And is exhausted from the exhaust line 12.

That is, NH ₃ introduced from one line
Is decomposed by the heater 8 and only hydrogen is exhausted through the hydrogen-permeable Pd alloy film 17 in the hydrogen removing device 9, so that hydrogen generated by decomposition of NH ₃ is not introduced into the reaction furnace. In the second embodiment, as in the first embodiment, the pipe length after the heater 8 should be as short as possible in order to suppress the recombination of the decomposed species. Removal device 9, switching valve 1
1 is arranged.

Next, AlG using the growth apparatus shown in FIG.
A method for growing an aInN-based light emitting device will be described. The structure of the element is the same as in FIG. The heater 8 for decomposing NH _{3 in} FIG. 4 is heated to 1000 ° C., and the hydrogen removing device 9 is evacuated from the exhaust line 12 while heating to 400 ° C. The switching valve 11 allows NH ₃ to be supplied to the reaction furnace through the bypass line 10. In this state, the pressure of the reaction furnace is set to the atmospheric pressure, the sapphire substrate 21 is heated to 1100 ° C., and the substrate surface is cleaned for 20 minutes by flowing 20 l / min of hydrogen. Next, the substrate temperature was set to 550 ° C., H ₂ was used as a carrier gas, and TM was used.
A is supplied at 9 μmol / min from the line 2 and NH ₃ is supplied at 3.5 l / min from the bypass line 10 to grow the AlN buffer layer 22 to a thickness of 35 nm. Next, the substrate temperature is set to 105
The temperature is raised to 0 ° C., and TMG is supplied at 50 μmol / min and SiH ₄ is supplied at 10 nmol / min from the line 2, and NH ₃ is supplied at 7 l / min from the bypass line 10 to grow the n-type GaN cladding layer 23 to 4 μm. . n-type GaN cladding layer 23
After the growth, the switching valve 11 is operated to set the NH ₃ to be supplied to the reaction furnace through the heater 8 for decomposition and the hydrogen removing device 9. Next, the substrate temperature was lowered to 800 ° C., and TMG was supplied at 7.7 μmo using N ₂ as a carrier gas.
1 / min, 3.4 μmol / min of TMI and 3 n of SiH ₄
mol / min from the second line, NH ₃ is decomposed by a heater 8 for decomposing 20l / min, after removing the hydrogen produced decompose hydrogen removing apparatus 9 is supplied to the reactor an In _0.3 Ga
_{A 0.7} N single quantum well active layer 24 is grown to a thickness of 2 nm. Next, 7.7 μmol / min of TMG and 0.7 μmol of TMA
/ Min and Cp ₂ Mg at 0.2 μmol / min from the line 2, NH ₃ was decomposed at 20 l / min by the decomposition heater 8, and the hydrogen removed by the hydrogen removing device 9 was removed.
The p-type Al _0.1 Ga _0.9 N protective layer 5
nm. Next, the substrate temperature was raised to 1050 ° C.
MG 50 μmol / min, Cp ₂ Mg 0.2 μmol
7 / min of NH ₃ is decomposed by a decomposition heater 8 from a line of 2, and hydrogen generated by decomposition by a hydrogen removing device 9 is removed, and then supplied to a reaction furnace to supply a p-type GaN clad layer 25. Is grown to 300 nm. Next, a dry etching process is performed to partially expose the n-type GaN cladding layer 23, and the Ti / Al-n-type electrode 27, the Ni-p-type transparent electrode 2
8 and the Au-p type electrode 29 are deposited to produce the light emitting device shown in FIG.

When performing InGaN growth as described above, NH ₃ is heated and decomposed by a decomposition heater 8, and then guided to a hydrogen removing device 9 to remove generated hydrogen and supply it to a reaction furnace. As a result, hydrogen that lowers the rate of In incorporation is not supplied onto the substrate.
An InGaN crystal having a high composition ratio can be obtained. Similarly, in the growth of Mg-doped AlGaN and p-type GaN of Mg-doped GaN, hydrogen, which causes the film to have a high resistance, is not supplied onto the substrate. Therefore, it is necessary to perform annealing for activating Mg. There is no. In this embodiment, p-type GaN having a carrier concentration of 1 × 10 ¹⁸ / cm ³ or more can be obtained without annealing.

(Embodiment 3) Next, a third embodiment will be described with reference to FIG. In FIG. 6, 1 is N of group V raw material.
Line for supplying H ₃ , 2 for TMG, T of group III raw material
A line for supplying an organic metal material such as MA, TMI, n-type impurity material SiH ₄ and p-type impurity material Cp ₂ Mg,
3 is an N ₂ supply line for adjusting the degree of mixing of each raw material, 4 is a reactor, 5 is a susceptor, 6 is a sapphire substrate, 7 is a work coil for high frequency heating, and 8 is a heater for decomposing NH ₃ , 9 is a hydrogen adsorption device, 10 is a bypass line, 11 is a switching valve, 12 is an exhaust line, and 19 is a reflector. The hydrogen adsorption device 9 has a structure similar to that of FIGS. In the present embodiment, the heating heater 8, the hydrogen adsorption device 9, and the switching valve 11 are installed inside the reaction furnace 4, and have a structure in which the length of the piping after the heating heater 8 is minimized. In addition, a reflection plate 19 is installed in the hydrogen adsorption device 9 and the switching valve 11 so that the temperature does not rise more than the influence of the radiation heat from the susceptor.

In the third embodiment, the heater 8
After decomposing H ₃ , recombination of decomposed species can be suppressed to the maximum, and hydrogen can be removed more efficiently. Note that the hydrogen removal apparatus using the Pd alloy film described in Embodiment 2 may be installed in a reaction furnace as in this embodiment. Further, although using NH ₃ as a group V raw material in all embodiments, t-Bu having a NH bond in addition to NH ₃
-NH ₂ (tertiary butyl amine), (i-Pr) 2
-NH (diisopropylamine), materials such as NH ₂ NH ₂ (hydrazine) may be as a group V raw material for growing device in accordance with the present invention.

Further, for the decomposition of the group V source gas, heat decomposition is performed by heating only to 1000 ° C. or higher with a heater, but Ni—Co—Al ₂ O ₃ and Ni—Co—
If an NH ₃ decomposition catalyst such as Al ₂ O ₃ is used, the decomposition temperature can be increased to 30.
It is possible to lower the temperature to 0 to 700 ° C. Therefore, the above-mentioned NH ₃ decomposition catalyst is sealed inside the decomposition device 8,
Decomposition may be performed by heating to 00 ° C. and flowing a group V source gas.

[0032]

As described above, the apparatus for decomposing the group V raw material, the apparatus for adsorbing and removing the hydrogen generated by the decomposition with the hydrogen storage alloy, or the hydrogen permeation are provided in the pipe for supplying the group V raw material to the reaction furnace. By equipping the membrane with a device to remove hydrogen,
Hydrogen generated by decomposition of the group V raw material is not supplied into the reactor.

In a device for adsorbing and removing hydrogen by means of a hydrogen storage alloy, the ability to cool and heat the hydrogen storage alloy improves the hydrogen adsorption capacity, and the desorption of the adsorbed hydrogen regenerates the hydrogen adsorption capacity. Activation is possible.

According to the growth apparatus and the growth method of the present invention, I
It is possible to improve the incorporation rate of In during the growth of nGaN.
An aN crystal can be obtained. Further, with respect to the growth of p-type GaN, hydrogen generated by thermal decomposition of the group V raw material, which is a factor for inactivating the p-type dopant Mg, is not supplied onto the substrate, and M
Since inactivation of g does not occur, it is not necessary to perform annealing in a nitrogen atmosphere after MOCVD growth, so that the process can be simplified, and there is no thermal damage due to annealing and no diffusion of dopant occurs. The element characteristics can be improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing a growth apparatus according to a first embodiment of the present invention.

FIG. 2 is a diagram showing an example of a hydrogen adsorption device used for the growth device according to the first embodiment of the present invention.

FIG. 3 is a diagram showing an example of a hydrogen adsorption device used for the growth device according to the first embodiment of the present invention.

FIG. 4 is a diagram illustrating a growth apparatus according to a second embodiment of the present invention.

FIG. 5 is a diagram showing an example of a hydrogen adsorption device used for a growth device according to a second embodiment of the present invention.

FIG. 6 is a diagram illustrating a growth apparatus according to a third embodiment of the present invention.

FIG. 7 is a diagram showing a conventional growth apparatus.

FIG. 8 is a diagram illustrating an example of an AlInGaN-based light emitting device structure.

FIG. 9 is a diagram showing a conventional example of hydrogen removing means.

[Explanation of symbols]

N ₂ supply line for adjusting the degree of mixing of the line 3 each raw material supplying line 2 III group material and the p-type impurity material and n-type impurity source for supplying NH ₃ of 1 V group material 4 reactor 5 susceptor 6 Sapphire substrate 7 Work coil for high frequency heating 8 Heater for decomposing NH ₃ 9 Hydrogen adsorption device, hydrogen removal device 10 Bypass line 11 Switching valve 12 Exhaust line 13 Hydrogen storage alloy 14 Cooling jacket 15 Heater 16 Filter 17 Hydrogen permeable membrane Reference Signs List 21 sapphire substrate 22 AlN buffer layer 23 Si-doped n-type GaN clad layer 24 InGaN active layer 25 Mg-doped p-type AlGaN protective layer 26 Mg-doped p-type GaN clad layer 27 n-type electrode 28 p-type transparent electrode 29 p-type electrode

Claims (5)

[Claims] 1. A growth apparatus for growing a nitride semiconductor thin film using a compound having an NH bond as a group V raw material,
The supply pipe of the group V raw material is provided with a means for decomposing the group V raw material, a means for adsorbing hydrogen generated by the decomposition of the group V raw material with a hydrogen storage alloy, and a means for cooling and heating the hydrogen storage alloy. A nitride semiconductor thin film crystal growth apparatus characterized by the following. 2. A growth apparatus for growing a nitride semiconductor thin film using a compound having an NH bond as a group V material.
An apparatus for growing a nitride semiconductor thin film crystal, comprising: means for supplying a group V source material; means for decomposing the group V source material; and means for removing hydrogen generated by decomposition of the group V source material by a hydrogen permeable membrane. 3. A growth method for growing a nitride semiconductor thin film using a compound having an NH bond as a group V raw material,
A method for growing a nitride semiconductor thin film crystal, characterized in that hydrogen generated by decomposition of a group V material is adsorbed by a hydrogen storage alloy and then supplied onto a substrate. 4. A growth method for growing a nitride semiconductor thin film using a compound having an NH bond as a group V raw material,
A method for growing a nitride semiconductor thin film crystal, comprising selectively removing hydrogen generated by decomposition of a group V material by a hydrogen permeable film and then supplying the hydrogen to a substrate. 5. A nitride semiconductor light-emitting device manufactured by the growth method according to claim 3.