JPH0936419A - Semiconductor device containing nitrogen - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the quality of a III-V compound semiconductor containing nitrogen and In by specifying the variation in the concentration of In atom within a specified region from the surface of an InN layer. SOLUTION: Assuming the thickness of an InN growth layer 123 is (t), variation in the concentration of in atom is set within ±15% in a region of 0.2t-0.6t from the surface of InN growth layer. More specifically, In is distributed uniformly in an active layer and the quality of a III-V compound semiconductor 123 containing nitrogen and In is enhanced. When 1,4-diazobicyclo (2, 2, 2) octane is used as the source of N at the time of vapor phase epitaxial growth of III-V compound semiconductor 123 containing nitrogen and In, melting point is set in the range of 158-160 deg.C and sublimation takes place at a temperature lower than the melting point. Since a low temperature vapor phase epitaxial growth is realized and thermal diffusion of In is controlled, the ratio of concentration (α) between N and In can be sustained constant (within ±15% for some value).

Description

Detailed Description of the Invention

[0001]

The present invention relates to indium nitride (In
N) or gallium nitride / indium (GaInN), etc.
The present invention relates to a semiconductor device such as a field-effect transistor or a light emitting diode having a laminated structure including a nitrogen-containing III-V group compound semiconductor layer containing n, and in particular, a nitrogen-containing III containing In that brings high performance of the semiconductor device III- The present invention relates to a semiconductor device having a laminated structure including a group V compound semiconductor layer.

[0002]

2. Description of the Related Art InN is one of nitrogen-containing III-V compound semiconductors having a forbidden width of about 2 eV at room temperature. Therefore, it has been attracting attention as a light emitting layer material for a light emitting diode (LED) that emits orange light having a wavelength of about 620 nm. Further, gallium nitride (GaN) containing In is used as a light emitting layer of a blue LED (for example,
S. Nakamura et al., Appl. Phys. Let
t. 64 (13) (1994), 1687. ).

In such a laminated structure for semiconductor device use, a nitrogen-containing III-V group containing In, such as InN or GaInN, which is used as a functional layer such as a light emitting layer, which is important for realizing the function of the semiconductor device. Compound semiconductors are MO
It is obtained by a vapor phase growth method such as VPE (also called MOCVD or OMVPE) or MBE.

It is said that InN composed of In atoms and N atoms is already decomposed at about 620 ° C. in vacuum ("Compound Semiconductor Device", edited by Japan Society for Promotion of Industrial Technology, New Materials Technology Committee (September 15, 1973). , Japan Industrial Technology Promotion Association, p. 397) It is a substance that is easily decomposed. Also,
GaInN, which is easy to decompose because it uses InN as the base material, is actually grown at a high temperature of about 800 ° C. (Shuji Nakamura, Japan Society for the Promotion of Science, Photoelectric Interconversion, 125th Committee, 148th Workshop Material (May 27, 1994), 1
page). Moreover, the growth is carried out by supplying the In raw material in a considerably excessive amount to the growth reaction system. During growth at a high temperature, In is volatilized from the growth layer, so that the stoichiometric disequilibrium of the group III atoms such as In and the group V atoms such as N constituting the growth layer is unbalanced. This is to suppress the increase.

Nitrogen-containing In containing InN, GaInN, etc.
Ammonia (NH ₃ ) has been conventionally used as a raw material for N when vapor-depositing the III-V compound semiconductor layer by the MOVE method or the like. However, NH ₃ is relatively difficult to thermally decompose. Also, since the decomposition reaction is reversible,
Even if a nitrogen gas (N ₂ ) which is a group V atom constituting the nitrogen-containing III-V group compound semiconductor layer or a nitrogen gas (N ₂ ) in which N atoms are bonded to each other is released by the decomposition, these decomposition products A part of them again becomes NH ₃ with hydrogen atoms (H) or hydrogen gas (H ₂ ) generated by decomposition, and tries to maintain a chemical equilibrium state. For this reason,
In the conventional vapor phase growth using NH ₃ as the N source, the nitrogen-containing nitrogen having a stoichiometric composition of the concentration of N atoms under the growth environment is used.
There is a problem that the height cannot be increased sufficiently to obtain a III-V compound semiconductor layer. Empirically, it is considered that sufficient N atoms cannot exist in the vapor phase growth environment unless the growth temperature is set higher than 800 ° C.

On the other hand, as a vapor phase growth material for In, which is a group III atom constituting InN, especially in MOVPE, trimethylindium ((CH ₃ ) ₃ In) or triethylindium ((C ₂ H ₅ ) ₃ In) is used. ) And other aliphatic In compounds and cyclopentadienylindium (C ₅ H ₅ I
n) and other alicyclic In compounds (J. Cryst.
th, 107 (1991), 360. ) Is conventionally used. These organic In compounds are generally easily decomposed by heat, which is the reason why they are used as a raw material for the pyrolysis vapor phase epitaxy (MOVPE) method. For example, C ₅ H ₅
In emits In atoms at a low temperature of about 270 ° C. (50th
The Japan Society of Applied Physics Academic Lecture Meeting (September 27, 1989-30)
Sun) Lecture No. 30a-W-9 (Lecture Proceedings First Volume 31)
Page 5)). That is, NH ₃ is used as the N source and the organic In compound is
In vapor phase growth using an n source, a large amount of In atoms can be present in the growth reaction system symmetrically with N atoms. The quantitative imbalance between N atom and In atom under the growth environment is not stoichiometrically balanced in composition, I
There is a drawback that a growth layer in which the concentration of n atoms is equivalently higher than the concentration of N atoms is provided. Due to this, for example, I
In the case of nN, the concentration ratio of In and N atoms was not constant even in the deep region of the layer, leading to unstable crystal characteristics.

In is a low melting point metal having a melting point of about 157 ° C. Therefore, it tends to be extremely diffused at a high temperature. In particular, for example, in an InN growth layer obtained by a conventional vapor phase growth method using NH ₃ and an organic In compound such as (CH ₃ ) ₃ In as raw materials of Group V and Group III,
Due to the imbalance between the amount of the decomposition products containing N such as N atoms existing in the growth reaction system and the amount of the decomposition products containing In such as In, In is usually in an excessive state. This stoichiometrically excess In diffuses more at high temperatures,
The exudates on the surface of the N growth layer and the exuded In fuses with each other to cause precipitation of In metal on the surface of the growth layer. Therefore, the concentration of In atoms in the vicinity of the surface of the growth layer is extremely higher than the concentration of In atoms in the inside of the growth layer.

As an example, NH ₃ / C ₅ H ₅ In / using NH ₃ as the N source and C ₅ H ₅ In as the In source is used.
In the H ₂ growth reaction system, the temperature is 80
FIG. 1 shows a conventional example of the distribution of the concentration of In atoms in the InN growth layer on the sapphire substrate at 0 ° C. in the depth direction. This concentration distribution in the depth direction is determined by secondary ion mass spectrometry (SIMS
Abbreviated. ). Further, it was confirmed that In metal was deposited on the surface of this InN growth layer. As shown in the figure, from the vicinity of the interface between the substrate and the InN growth layer, I
Toward the surface of the InN growth layer where precipitation of n is observed
The concentration is gradually increasing. That is, the InN layer does not always have a constant In concentration throughout the layer. This is one reason why an InN layer having stable characteristics cannot be obtained with good reproducibility.

Here, nitrogen containing InN or nitrogen containing In and N
The concentration of N atoms in the III-V group compound semiconductor layer is C _N (number / cm ³ ), and the concentration of In atoms is C _In (number / cm ³ ).
Let be represented by. The total atomic weight of In having an atomic weight of 114.82 and N having an atomic weight of 14.00 is 128.82.
For example, since the density of InN is 6.88 g / cm ³ , the number of In atoms per unit volume is 3.22 × 10 ^22.
The number / cm ^3. For InN binary crystals, the number of N atoms is also equal. Ratio of C _{In to} C _N (C
_{Let In} / C _N ) be represented by α. If α = 1, C _N = C
_In , which means that it is a stoichiometric stoichiometric InN growth layer. When α> 1,
C _In > C _N , which means that In atoms are in excess of N atoms. Conversely, for α <1, C _N >
It becomes C _In , indicating that N atoms are present in excess. In the case of α> 1 or α <1, it means that the stoichiometric composition is InN in any case.

The value of α according to the present invention is expressed in relation to the depth (d) from the surface of the InN growth layer obtained by the conventional vapor phase growth method, for example. For the sample exhibiting the In concentration distribution shown in FIG. 1, α is overlaid on FIG. The InN growth layer is an InN growth layer having a film thickness of 100 nm, and d ≦ 1
Area near the surface of 2 nm, that is, 12 n from the surface of the growth layer
In the depth region of m or less, the maximum value of α is about 5. Therefore, the In atoms are excessive near the surface, and as a result, precipitation of In metal is visually observed on the surface of the InN growth layer as described above. In the depth region of d> 12 nm, C _In gradually decreases toward the {0001} sapphire substrate side due to thermal diffusion of In to the surface of the growth layer, and does not have a constant α value. That is, in the InN growth layer vapor-deposited by the conventional MOVPE method using NH ₃ which requires a high temperature for decomposition as an N source, InN growth layer due to thermal diffusion and precipitation of In atoms toward the growth layer surface. The equilibrium of the stoichiometric composition is broken inside the growth layer and
There was a shortage of atoms, and α was not constant.

When the concentration of In atoms is excessive on the surface, the surface of the originally transparent InN growth layer is colored brown, gray or black. Among semiconductor devices using a nitrogen-containing III-V group compound semiconductor layer, L which requires light transmittance
For ED etc., colored opaque nitrogen-containing III-V
Since the group compound semiconductor layer absorbs light emission, LE with high brightness
The result was that the provision of D was hindered.

The semiconductor device is not generally composed of only a single semiconductor layer. For example, a field effect transistor is generally composed of a laminated structure including a buffer layer, a channel layer (active layer), and sometimes a contact layer in total of three layers. Further, the LED has a laminated structure including a buffer layer, a light emitting reflection layer (DBR layer), a lower clad layer, a light emitting layer, an upper clad layer, a current diffusion layer, a contact layer, and the like. Therefore,
In order to form such a laminated structure for semiconductor device use, it is necessary to deposit another growth layer on the surface of the InN growth layer. When the concentration of In atoms near the surface of the InN growth layer is high and excess In exists near the surface, this excess In passes through the interface with the second growth layer deposited on the inside of the second growth layer. And diffuse into the crystallographic composition and electrical characteristics of the second growth layer. In addition, excessive In is accumulated at the interface with the second growth layer, and the expected interface physical properties cannot be obtained. In the high mobility transistor, where the physical properties of the interface are important for revealing the characteristics of the semiconductor device,
Accumulation of In atoms at the interface hindered the manifestation of characteristics.

In a nitrogen-containing III-V group compound semiconductor layer containing In such as InN, vapor deposition of these layers is the main cause of increase in concentration of In atoms or precipitation of In near the surface of the layer. In this case, NH ₃ which has been conventionally used as an N source is hardly decomposed. About 800
Since the decomposition temperature of the organic In compound is extremely low in comparison with the temperature at which NH ₃ is set to ℃ or higher and the decomposition product containing N atom or N is efficiently released, the content of NH ₃ contained in the vapor phase growth environment is increased. This is due to the imbalance in the ratio of the concentrations of N-decomposition products and In-containing decomposition products. If N atoms are sufficiently supplied to In atoms, an InN layer having an equivalent amount can be obtained. Alternatively,
On the contrary, an In compound having the same difficulty of decomposition as NH ₃ is
When used as a source, it is thought that the above-mentioned thermal decomposition equilibrium is obtained.

However, in the vapor phase growth of the III-V compound semiconductor layer, the growth rate of the growth layer depends on the supply amount of the group III atoms into the growth environment. If the supply amount of group III atoms into the growth environment is small, the growth rate will decrease. If the growth rate decreases, it is necessary to spend more time to obtain a growth layer having a target layer thickness. The distance an atom can reach thermal diffusion increases in proportion to the growth time. That is, for example, In
In MOVPE growth of N, by increasing the growth time, I
The diffusion distance of n becomes long, resulting in promoting the accumulation of In in the vicinity of the surface of the growth layer, which is not preferable.

[0015]

In order to overcome the conventional problems concerning the imbalance of the atomic concentration which constitutes such a nitrogen-containing III-V compound semiconductor layer containing In, it is necessary to use, for example, the heat of In. There is a first need for a new N source for low temperature decomposable vapor phase growth that results in low temperature film formation without significant diffusion. In addition, nitrogen containing In, such as InN containing In, etc.
Regulations related to the In concentration in the growth layer to be provided for improving the characteristics of the semiconductor device having the laminated structure including the III-V compound semiconductor layer, the growth layer surface, and the vicinity of the interface with other growth layers It is necessary to clarify the maximum value of α at. For example, in the InN layer, the In concentration inside the growth layer is constant, and α is stoichiometrically balanced close to 1 over the surface of the growth layer or the vicinity of the interface and the inside of the growth layer. Of course it is necessary. However, in reality, In may have a high thermal diffusivity as described above,
It is necessary to define a practical range for the constant In concentration and α. However, for the purpose of improving the characteristics of the excellent semiconductor device to date, a nitrogen-containing In containing III having excellent crystallinity, which has sufficient crystallinity III-
There is no known example of defining α in the present invention for obtaining a Group V compound semiconductor layer.

[0016]

That is, according to the present invention, in an InN layer deposited on a substrate, when the layer thickness of InN is t, 0.2 t or more and 0.6 t or more inside the surface of the InN layer are provided.
Provided is a semiconductor device including a nitrogen-containing III-V group compound semiconductor in which the change in In atom concentration is within ± 15% in the following region. In addition, the concentration of N atoms (C _N (pieces / cm
³ ). In atomic concentration (C _In (pieces / cm
³ ). ) (C _In / C _N , represented by numerical value α) is 0.2 t or more from the surface of the InN layer to the inside.
Provided is a semiconductor device which is constant within a region of 6t or less.
In particular, the present invention provides a semiconductor device in which the maximum value of α is 2 or less in the depth region less than the value given by 0.2t from the surface or the interface of the growth layer.

In order to suppress the thermal diffusion of In in the nitrogen-containing III-V compound semiconductor layer containing In, it is first necessary to use a low-temperature decomposable nitrogen-containing compound that causes a decrease in the growth temperature as the N source. is there. From the results of earnestly studied by the present inventors, for example, a nitrogen-containing heterocyclic compound containing a nitrogen atom as a ring-constituting atom, a nitrogen-containing compound such as an alicyclic compound containing nitrogen as a ring-constituting atom, etc. Has been found to be fit as an N source for vapor phase growth. Among these nitrogen-containing compounds, for example, 1H-pyrrol (Pyrrol)
e), 1,4-diazobicyclo (2,2,2) octane (1,4-Diazobicyclo (2,2,2) o
ctan) and orthophenylenediamine (1,2-diaminobenzene) (o-Phenylenediamine)
A compound such as e) is particularly suitable as an N source when vapor-depositing a nitrogen-containing III-V group compound semiconductor layer containing In. If these nitrogen-containing compounds are used as the N source, conventional N
Of H ₃ nitrogen-containing III -V compound semiconductor layer of a low temperature than the growth temperature at which vapor phase growth as N source, 500 ° C. to 70
The growth of the nitrogen-containing III-V compound semiconductor layer can be achieved at a low temperature of 0 ° C.

In particular, 1,4-diazobicyclo (2,2,2
2) Octane has a melting point of 158 ° C. to 160 ° C. and is a solid at room temperature, but has a property of already subliming at a temperature below the melting point. Sublimation pressure is 2.9 Torr at 50 ° C, 11
It becomes 83.4 Torr at 0 degreeC. Therefore, it has a sublimation pressure sufficient as a raw material for vapor phase growth applications at a temperature of 70 to 100 ° C. or lower, which is a heat resistant temperature of general valves, and a growth reaction for performing vapor phase growth of vapor of the raw material. It has the advantage that it can be easily added to the system.

By using these nitrogen-containing compounds which replace conventional NH ₃ as the N source, the temperature of the vapor phase growth process can be lowered, and the thermal diffusion activity of In can be suppressed. Therefore, the value of α in the vicinity of the surface of the growth layer such as InN can be reduced, and the value of α can be made constant over a wide range inside the growth layer. In the present invention, when the thickness of the InN layer is t, the InN layer in which C _In and α are constant within a region of 0.2 t or more and 0.6 t or less from the surface of the InN layer is used as a constituent layer of the laminated structure. . The constant value of C _in and α according to the present invention means that the value is within ± 15% with respect to a certain value in consideration of the analysis accuracy of the atomic concentration in the depth direction. The reason for setting ± 15% is that, if both C _In and α are stored in this range, the result of earnest study by the present inventor shows that
This is because the LED does not affect the characteristics of the semiconductor device such as the emission wavelength and the threshold voltage in the forward direction.

1,4 which is the above-mentioned new N-containing compound
-InN grown at 600 ° C. by using diazobicyclo (2,2,2) octane as an N source and using a vapor phase growth reaction system consisting of this, cyclopentadienyl In and hydrogen
FIG. 2 shows an example of C _N and C _{In in} the depth direction of the growth layer. The layer thickness (t) of the InN growth layer is 200 nm. 40 nm or more corresponding to 0.2 t from the surface of the growth layer, 0.8
C _In in a region of 160 nm or more in depth corresponding to t
And α are both constant.

Within the range of 0.2t to 0.6t, C _In
And α are defined as ± 15% because C _In beyond this range
This is because the equivalently unbalanced growth layer having a and α does not have good crystallinity, and even a desired amount of electrical elements such as specific resistance and mobility cannot be stably obtained. Therefore, in the case of a semiconductor device having a stacked structure having such an equilibrium growth layer exceeding ± 15%, for example, in a field effect transistor, a leak current between source / drain electrodes, This is because it has an adverse effect such as increasing the drift of the drain current.

In the case of growth of a nitrogen-containing III-V group compound semiconductor layer containing In, in which α is constant in the region of 0.2t or more and 0.6t or less, comparison of the vicinity of the surface less than 0.2t from the surface of the growth layer In the extremely shallow region, the maximum value of α hardly increases to 5 or more as in the conventional example. 0.2t or more 0.
If α is constant in the region of 6t or less, α is usually set to about 2 at maximum. If α <2 in a very small region with respect to the thickness of the entire growth layer near the surface of the growth layer, In
The nitrogen-containing III-V compound semiconductor layer containing is not opaque. Therefore, by defining α to be constant in the region of 0.2t or more and 0.6t or less, the accumulation of In near the surface of the growth layer caused by thermal diffusion of In is suppressed, and thus the LED is suppressed. It is possible to supply a growth layer that can be sufficiently applied to semiconductor devices such as. The area of 0.2t or more and 0.6t or less in the present invention means a continuous area. When regions where α and C _In are constant exist in the growth layer discontinuously, if the total size of the discontinuous regions is accommodated within a range of 0.2t or more and 0.6t or less. It's not good.

In the region closer to the substrate inside the growth layer that exceeds 0.6 t from the surface, it varies depending on the material of the substrate used and the like. C _N = C _In does not always exist in the growth layer deposited immediately above the surface of the substrate at the initial stage of growth.
However, C _N > C _In or C _In > C _N may be obtained depending on the surface treatment method of the substrate. It is desirable that α is constant even in the deep region on the substrate side inside the growth layer,
If such a situation occurs, if the growth operation is performed by intentionally changing the supply amount of the N source and the In source to the growth reaction system at the initial stage of growth, α is set to 1 You can also

The use of the low temperature decomposable nitrogen compound presented according to the present invention not only results in a stoichiometrically balanced nitrogen-containing III-V compound semiconductor growth layer containing In. For the vapor phase growth at low temperature brought about by the low temperature decomposability, materials such as glass and aluminum (Al) which cannot be used in the conventional vapor phase growth method using NH ₃ as the N source can be used as the substrate. Since glass materials and the like are much cheaper than conventional sapphire (alumina single crystal) and especially SiC single crystal, an economical effect such as a cheap semiconductor device is expected as a result.

The growth method of the nitrogen-containing compound semiconductor layer containing In having a constant α within the defined growth layer of the present invention is not limited to the MOVPE method. MBE method,
MO-MBE method, VPE method and CBE (Chemical)
The Beam Epitaxy method or the like may be used. The MOVPE method may be either a reduced pressure MOVPE method in which growth is performed in a reduced pressure environment or a normal pressure MOVPE method in which growth is performed at a pressure near atmospheric pressure. Regardless of which method is used, a suitable growth temperature is around 500 ° C to 700 ° C. Decompression MOVPE
In the method, the pressure is usually set to about 1 to 200 Torr, but also in the practice of the present invention, growth may be performed under a normal reduced pressure, and a specific pressure setting is not required.

[0026]

By making the distribution of In uniform in the active layer, the quality of the nitrogen-containing III-V group compound semiconductor layer containing In is improved.

[0027]

EXAMPLES The present invention will be described with reference to an example of forming an LED from a laminated structure including a nitrogen-containing III-V group compound semiconductor layer containing In. FIG. 5 shows a structural diagram of the LED structure obtained in this example. An n-type GaP single crystal doped with sulfur (S) having a plane orientation of (111) was used as a substrate (115).
The thickness of the substrate (115) was about 350 μm. The substrate (115) had a circular shape with a diameter of about 50 mm. Al is formed on the substrate (115) by the MOVPE method under normal pressure.
N, InN and GaN were sequentially grown to obtain a laminated structure for LED. An outline of the vapor phase growth equipment used is shown in FIG.

1,4-diazobicyclo (2,2,2) octane was used as the nitrogen source (101) for growing AlN, InN and GaN. This substance is stored in a stainless steel container (102) and placed in a constant temperature bath (10
The container (102) was kept at 70 ° C. by 7). 70 ° C
The sublimation pressure of 1,4-diazobicyclo (2,2,2) octane in the above is about 45 Torr.

In the container (102), the raw material carrying gas (11
As 0), high-purity hydrogen gas was circulated. The hydrogen gas containing the sublimed 1,4-diazobicyclo (2,2,2) octane was passed through the pipe (113-1) and the reaction vessel (1
08) pipe (111) or exhaust pipe (112)
Valves ((114-1) and (114-
It was supplied by the switching operation of 2)). Container (102)
The flow rate of the hydrogen gas, through which the raw material-transporting gas (110) was circulated, was changed for each target nitrogen-containing compound layer.

As the indium source (105), cyclopentadiene indium (Cyclopentadiene) is used.
yl Indium) (abbreviated as C ₅ H ₅ In: CpIn) was used. CpIn was stored in a stainless steel container (106). The container (106) is a thermostat (1
The temperature was maintained at 60 ° C according to 07). As a gallium (Ga) source (103), trimethylgallium ((CH ₃ )
₃ Ga) was used. The Ga source (103) is housed in a stainless steel container (104), and is kept at 0 ° C. in a constant temperature bath (107).
Held. Trimethyl aluminum ((CH ₃ ) ₃ Al) was used as the Al source (119). The aluminum source (119) was stored in a stainless steel container (120) and kept at 25 ° C. by a constant temperature bath (107).

In the container (106) accommodating CpIn, purified high-purity hydrogen gas (1) is used as a raw material carrying gas (1).
The hydrogen gas containing CpIn, which has circulated as 10) and is sublimated, does not communicate with the pipe (111) or the reaction container (108) that communicates with the reaction container (108) through the pipe (113-2). Other gas containers (10
8) It was circulated in any of the exhaust pipes (112) connected to the pipe for discharging to the outside. The circulating pipe is a valve ((11
4-5) and (114-6)) were opened and closed for selection.

A container (10 for storing (CH ₃ ) ₃ Ga
4) and (CH ₃ ) ₃ Al are stored in a container (119) containing purified high-purity hydrogen gas as a raw material carrying gas (110), and (CH ₃ ) ₃ Ga or (CH _{3 3} ) ₃ Al was bubbled. (CH ₃ ) ₃ Ga
Alternatively, the raw material carrying gas (110) accompanied with (CH ₃ ) ₃ Al is pipe ((113-2) or (113-
4)) through the valve ((114-3) or (114
-4) and (114-7) or (114-8)) were switched to introduce into the pipe (111) or the exhaust pipe (112) leading to the growth reaction container (108).

At the stage before the film formation is started, the containers ((102), (104), (10) for accommodating the above raw materials are stored.
6) and (119)), and the raw material carrying gas (11
0) was poured. Before the film formation is started, the pipe (111) for the raw material carrying gas (110) accompanied by the vapor or sublimation gas of the raw material of the group V element or the group III element
Valves ((114-1), (114
-3), (114-5) and (116-7)) are closed, and conversely the valves ((114-2), (114-4), (114-6) communicating with the exhaust pipe (112). ) And (114-8)) were opened. Therefore, before starting the film formation, the raw material carrying gas (110) accompanied by the vapor or the sublimation gas of the raw material of the group V element or the group III element is allowed to flow to the exhaust pipe (112). I was there. This is in advance to ensure the temporal stability of the flow rate of the raw material carrying gas (110).

The above substrate (115) is placed in a reaction vessel (10
It was placed on the heating element (117) in 8). After replacing the inside of the reaction vessel (108) with an inert gas, the pipe (11
Hydrogen gas used as a carrier gas (109) through 1) at a flow rate of 8.0 l / min in the reaction vessel (108)
Distributed inside. Twenty minutes after starting the flow of the carrier hydrogen gas (109) into the reaction vessel (108), energization of the heating element (117) was started to raise the temperature of the substrate (115) from room temperature to 600 ° C. Let After reaching the same temperature, the same temperature was maintained for 10 minutes to stabilize the substrate temperature.

After that, a hydrogen gas (110) for transporting the raw material, which contains 1,4-diazobicyclo (2,2,2) octane vapor as the N source (101), is introduced into the exhaust pipe (112). Valve (114-2) for closing the valve (114-1) is opened at the same time, and the pipe (11-1) is opened.
1) Joined inside. 1,4-diazobicyclo (2,4) joined to a pipe (111) leading to a reaction vessel (108)
2,2) Hydrogen gas for transporting raw materials containing octane vapor (1
10) was carried into the reaction vessel (108) by the hydrogen carrier gas (109). The raw material carrying gas for the N source may be an inert gas such as argon (Ar) or nitrogen (N ₂ ) in addition to hydrogen. Further, for example, a mixed gas of hydrogen gas and Ar gas may be used.

1,4-diazobic acid used as N source (101)
Hydrogen carrier containing chlorine (2,2,2) octane vapor
5 minutes after introducing the gas (109) into the reaction vessel (108)
After that, (CH_Three )_Three Raw material carrying gas accompanied by Al
Installed to introduce (110) into the exhaust pipe (112).
The digit valve (114-8) is closed, and conversely the valve (11-8) is closed.
4-7) was opened. As a result, the Al source (11
9) (CH_Three )_Three Guide Al into the reaction vessel (108)
And put an n-type AlN layer (121) on the substrate (115).
Deposited. The n-conductivity type AlN layer (121) has a volume concentration
From high-purity hydrogen gas containing about 5 ppm disilane
The doping gas from the cylinder (124) is 10cc /
By supplying Si at a rate of
I got it. The flow rate of this doping gas is the AlN layer (12
Carrier concentration of 1) is about 1 x 10¹⁸cm ^-3To be
It has been arranged. The doping gas is the N source (1
01) was supplied to the reaction vessel (108) at the same time as piping
Merged with (111).

In obtaining the AlN layer (121), N
The flow rate of hydrogen gas (110) for carrying the source (101) was set to 250 cc / min. The flow rate of hydrogen bubbling (CH ₃ ) ₃ Al was 35 cc / min. Hydrogen gas accompanied by the gas of the sublimated N source (101) and (CH
₃ ) Hydrogen gas containing vapor of ₃ Al is used in the reaction vessel (108)
The supply was continued through the inner gas nozzle (118) for 40 minutes to deposit a 0.3 μm AlN layer (121).

After the growth of the AlN layer (121), once (CH
₃ ) A valve (11) serving as an inlet for the hydrogen gas (110) containing the vapor of ₃ Al into the pipe (111) communicating with the reaction vessel.
4-7) is closed, and allowed to flow into the valve (114-8) Conversely as open (CH ₃₎ hydrogen gas containing ₃ Al of steam in the exhaust pipe (112). At the same time, the introduction of the dopant gas into the pipe (111) was temporarily stopped. The hydrogen gas containing the N source (101) vapor was kept introduced at the same flow rate and introduced into the pipe (111).

A hydrogen gas (110) for transporting a raw material containing a vapor of (CH ₃ ) ₃ Al and a pipe (11) for a dopant gas.
After 5 minutes have passed since the introduction to 1) was stopped, sublimated C
A raw material-transporting hydrogen gas (110) containing a pIn gas was introduced into the pipe (111) by switching valves ((114-5) and (114-6)). The volume concentration of the p-type impurity (dopant) is about 5%.
A mixed gas of 0 ppm of dimethyl zinc and high-purity hydrogen was supplied from a gas cylinder (126) at a flow rate of 12 cc / min.
The hydrogen gas containing the sublimation gas of CpIn and the gas containing the dopant were sprayed on the substrate (115) continuously for 60 minutes through the nozzle (118) in the growth container (108).
As a result, a p-type InN layer (123) having a carrier concentration of about 1 × 10 ¹⁷ cm ⁻³ was deposited. Thickness is 0.1μ
m. When 60 minutes have passed, the valve ((1
14-5) and (114-6)) are opened and closed to stop the introduction of the hydrogen gas (110) for raw material transport containing CpIn into the pipe (111), and conversely, to exhaust it (112). Introduced to the side. Piping (1) for hydrogen gas (110) for transportation containing p-type doping gas and N source (101)
11) is introduced into the raw material carrying gas (11) containing CpIn.
It continued regardless of the change of the flow path of 0).

Hydrogen gas for raw material transportation containing CpIn (11
After changing the flow path of 0) for 5 minutes, the Ga source (10
The valve (114-4) is changed from the open state to the closed state in order to introduce the hydrogen gas (110) for transporting the raw material containing (CH ₃ ) ₃ Ga described in ₃ ) into the exhaust pipe (112), and conversely the valve (114 -3) was opened. This gives (CH ₃ ) ₃
Ga is introduced into the pipe (111) through the pipe (113-2), and the hydrogen carrier gas (1
09), a raw material carrying gas (11) containing an N source (101)
0) and the p-type doping gas, and the reaction vessel (1
08), and a p-type GaN layer (122) was grown. The flow rate of the raw material carrying gas (110) of (CH ₃ ) ₃ Ga was set to 30 cc / min. The growth of the GaN layer (122) was continued for 50 minutes after starting the merging of the hydrogen gas (110) for transporting the raw material containing (CH ₃ ) ₃ Ga into the pipe (111). The thickness of the GaN layer (122) was 0.3 μm. The carrier concentration of the p-type doping gas is about 1
It was set to 20 cc / min so as to be 0 ¹⁷ cm ^-3 .

Nitrogen-containing content of the obtained laminated structure III-
Ga, In, A which are the constituent elements of the group V compound semiconductor layer
FIG. 4 shows the distribution of the l and N elements in the depth direction by SIMS analysis. In particular, for the InN layer (123), the region of 0.1 μm from the interface with the AlN layer (121) to the interface with the GaN layer (122) corresponds to the layer thickness of the InN layer. Al
From the interface with the N growth layer (121) (point A in the figure), I
Through the point B of 0.02 μm depth (d = 0.02 in the text) into the nN growth layer (123), the interface (d = 0.10) with the GaN growth layer (122) (point C _N described in the text in a continuous area of 0.08 μm leading to C)
The ratio α between C _In and C _In is almost constant. Based on the quantitative values of C _N and C _In, the analytical sensitivity depending on the element to be analyzed was corrected, and α in the text was calculated. That is, in the range of 0.
Within the range of 2t ≦ d ≦ 0.6t, at least α described in the text was a constant value of 1.04. Also, d <0.0
The maximum value of α was suppressed to 1.06 even in the region near the interface with the AlN growth layer of No. 2 (point A). Therefore, the InN growth layer (123) was not colored in brown, gray or black.

AlN growth layer (121), InN growth layer (123) and G deposited on the surface of the GaP substrate (115).
A strip-shaped center electrode (128) and a peripheral electrode (129) facing the strip-shaped center electrode (128) are formed on the surface of the laminated structure (116) including the aN growth layer (122) by applying a patterning method using a known photolithography technique. Formed. The center electrode (128) was provided on the GaN growth layer (122) which is the outermost layer of the laminated structure. The width of the center electrode (128) is about 9
The length was 0 μm and the length was about 350 μm. Center electrode (1
The peripheral electrode (129) facing 28) was provided on the AlN growth layer (121). The peripheral electrode had a width of about 75 μm and a length of about 350 μm. Center and surroundings ((12
Both 8) and (129)) electrodes were made of Al.

In this example, binary compounds AlN and I are used.
Although the laminated structure for an LED is composed of a total of three layers of nN and GaN, the combination, conduction type, film thickness and carrier concentration of the nitrogen-containing III-V group compound semiconductor layers constituting the laminated structure are not limited thereto. For example, AlGaN and GaN
A laminated structure including a heterojunction with Of course, there is no special regulation on the number of layers constituting the laminated structure. Further, the semiconductor device having the laminated structure described in this embodiment is not limited to the LED.

The above-mentioned 1,4-diazobicyclo (2,4
2,2) I grown by low temperature vapor deposition using octane as N source
It was found that visible light having a center wavelength in the red band of about 650 nm was emitted from the LED structure composed of the laminated structure including the nitrogen-containing III-V group compound semiconductor layer containing n. In an energization deterioration test in which the operating current was set to 20 mA, the change in emission wavelength with the increase of energization time was observed in the conventional LED having a laminated structure including a nitrogen-containing III-V group compound semiconductor layer containing In. It was recognized that the number was small compared to the above. As a specific example of the amount of change in the emission wavelength immediately after applying a DC operating voltage of 4.5 V between the electrodes,
In the conventional LED, the emission wavelength shifts to the long wavelength side of about 25 nm, whereas in the LED according to the present embodiment, the shift amount of the emission wavelength to the long wavelength side is suppressed to about 5 nm. Conventional L
In the ED, the luminous intensity was also deteriorated with the change of the emission wavelength accompanying the energization, the luminous intensity was decreased by about 15% immediately after the energization, and there was a tendency that the luminous intensity was gradually decreased by continuing the energization. On the other hand, in the LED according to the present invention, the luminous intensity decreased about 5% immediately after energization, but the luminous intensity tended to be constant in the subsequent energization. The luminous intensity at the time of energization which became almost constant was about 45 millicandelas, and even at this time, the luminous intensity was about 1.4 times that of the LED of the conventional example. One of the causes of these changes in wavelength and emission intensity over time is migration of indium atoms to the vicinity of the hetero interface due to an electric field. In the LED according to the present invention, since the temporal change of the emission wavelength and the luminous intensity is suppressed to be low,
It is considered that defining α has the effect of suppressing the accumulation of indium atoms at the hetero interface or the like due to the movement of indium atoms in the layer due to the electric field generated by the application of the operating voltage or the heat generated. In summary, defining α is an optically transparent In that excels in light emission transparency.
It is possible to provide an LED having a laminated structure including a nitrogen-containing III-V group compound semiconductor layer that provides an N layer and thus improves emission light intensity and that has little deterioration of emitted light and emission wavelength with time.

The 1,4-diazobicyclo (2,2,2) octane used in this example is an example of a heterocyclic compound containing two nitrogen atoms as hetero atoms, and the nitrogen source is the nitrogen-containing compound. It is not limited to compounds.

[0046]

The characteristics of a semiconductor device having a laminated structure provided with a nitrogen-containing III-V group compound semiconductor layer containing In are improved. Particularly, in the case of the LED, the operation reliability and the emission intensity are increased.

[Brief description of drawings]

FIG. 1 is a diagram showing a distribution of In concentration and C _In / C _N ratio (α) in a conventional InN layer in the depth direction.

FIG. 2 shows the In concentration and C _In / C of the InN layer according to the present invention.
It is a figure which shows the distribution of _N ratio ((alpha)) in the depth direction.

FIG. 3 is a schematic view of a vapor phase growth apparatus used for carrying out the present invention.

FIG. 4 is a diagram showing distributions of constituent elements of a laminated structure according to an example in the depth direction.

FIG. 5 is a schematic view of a semiconductor device (LED) according to an example.

[Explanation of symbols]

 (101) Nitrogen source (102) Nitrogen source storage stainless steel container (103) Gallium (Ga) source (104) Gallium source storage stainless steel container (105) Indium (In) source (106) Indium source storage Stainless steel container (107) Constant temperature bath (108) Growth reaction container (109) Hydrogen carrier gas (110) Raw material transfer gas (111) Pipe leading to growth reaction container (112) Exhaust pipe (113) Pipe (114) Valve (115) Substrate (116) Laminated structure (117) Heater (118) Nozzle (119) Aluminum source (120) Aluminum source container for stainless steel (121) Aluminum nitride (AlN) growth layer (122) Gallium nitride (GaN) Growth Layer (123) Indium Nitride (InN) Growth Layer (1 24) N-type layer forming doping gas storage cylinder (125) N-type layer forming doping gas pipe (126) P-type layer forming doping gas storage cylinder (127) P-type layer forming doping gas pipe (128) Center electrode (129) Peripheral electrode

Claims (3)

[Claims] 1. In a semiconductor device having a laminated structure including an InN growth layer deposited on a substrate, when the layer thickness of the InN growth layer is t, 0.2 t or more from the surface of the InN growth layer toward the inside. In the region of 0.6 t or less, In
A nitrogen-containing semiconductor device provided with a nitrogen-containing III-V group compound semiconductor layer, characterized in that the concentration change of atoms is within ± 15%. 2. The N atom concentration C _N and In in the InN growth layer.
The variation of the ratio α (α = C _In / C _N ) with the atomic concentration C _In is
When the layer thickness of the InN growth layer is t, it is within ± 15% in a region of 0.2t or more and 0.6t or less from the surface to the inside of the InN growth layer.
The nitrogen-containing semiconductor device according to. 3. The nitrogen-containing semiconductor device according to claim 2, wherein the maximum value of α is 2 or less.