JPH08167737A - Group iii nitride semiconductor light emitting device - Google Patents

Abstract

PURPOSE: To obtain a multicolor light emitting device by combining a first light emitting element composed of a group III nitride semiconductor and light emitting elements which emit other colors of light rays. CONSTITUTION: Layers 2-6 composed of group III nitride semiconductors (Alx Gay In1-x-y N, where x, y, and y=y include '0') are successively formed on a sapphire substrate 1 and an electrode 7 connected to the p-layer 6 and another electrode 8 connected to the n<+> -layer 4 containing a carrier at a high concentration are respectively formed on the layers 6 and 3. The electrode 7 and 8, a p-layer 6, a light emitting layer 5, and an n<+> -layer 4 constitute a first light emitting element. In addition, a semiconductor element provided at least with layers 10-12 composed of group III arsenides which are formed by epitaxial growth is formed on the n<+> -layer 3 containing a carrier at a high concentration. Electrodes 9 and 8, p-layer 12, and n-layer 11 constitute a second light emitting element. Therefore, a light emitting device which can emit multicolor light is obtained.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a group III nitride semiconductor and a group 3 nitride semiconductor.
The present invention relates to a light emitting device using a group arsenide semiconductor or a group 3 phosphide semiconductor.

[0002]

2. Description of the Related Art Conventionally, AlGaIn has been used as a blue light emitting diode.
Those using N-based compound semiconductors are known. Since the compound semiconductor is a direct transition type, it has been noted that it has high emission efficiency, and that blue, which is one of the three primary colors of light, is used as the emission color.

Recently, it has been revealed that also in an AlGaInN-based semiconductor, Mg can be doped to irradiate it with an electron beam or can be made into a p-type by heat treatment. As a result, instead of the conventional MIS type in which an n layer and a semi-insulating layer (i layer) are joined, AlGaN
, A Zn-doped InGaN light emitting layer and an AlGaN n layer have been proposed as a light emitting diode having a double hetero pn junction.

[0004]

By the way, the above-mentioned first light-emitting element made of a Group III nitride semiconductor is one of the three primary colors of light.
Therefore, it is desired to form a multi-color light emitting device by combining the first light emitting element and light emitting elements of other emission colors.

The present invention has been made to solve the above problems, and an object thereof is to provide a light emitting device capable of multicolor light emission based on a group III nitride semiconductor.

[0006]

According to the first aspect of the present invention, there is provided a group III nitride semiconductor (Al _x Ga _Y In _1-XY N; X = 0, Y = 0, X = Y = 0).
A semiconductor element having a layer made of at least a group 3 arsenide semiconductor formed by epitaxial growth on a layer made of a group 3 nitride semiconductor, or 3
One or a plurality of semiconductor elements each having a layer made of a group phosphide semiconductor.

According to the invention of claim 2, a group III nitride semiconductor (Al _x
Ga _Y In _1-XY N; including X = 0, Y = 0, and X = Y = 0), and a first light emitting device having an n-layer showing an n-conduction type and a p-layer showing a p-conduction type. It is characterized by having an n layer made of a group 3 arsenide semiconductor or a group 3 phosphide semiconductor formed by epitaxial growth on a group 3 nitride semiconductor layer, and a second light emitting element having ap layer.

According to a third aspect of the invention, in the first light emitting element, the n layer, the p layer, and the light emitting layer interposed therebetween sandwich a semiconductor having a narrow band gap with a semiconductor having a wide band gap. The structure is characterized by having a three-layer structure of double heterojunction.

Further, the invention according to claim 4 is characterized in that the second light emitting element is formed of GaAs or AlGaAs.

Further, the invention according to claim 5 is characterized in that the second light emitting element is formed after the surface of the group III nitride semiconductor layer is arsenicized or phosphinated. Further, the invention according to claim 6 is a compound semiconductor comprising an element forming a Group III nitride semiconductor and an element forming a second light emitting element between the second light emitting element and the Group III nitride semiconductor. Is formed.

[0011]

As described above, a semiconductor element made of a group III nitride semiconductor and a layer made of at least a group III arsenide semiconductor formed by epitaxial growth on a group III nitride semiconductor, or a group III group. Since one or a plurality of semiconductor elements each having a layer made of a phosphide semiconductor are provided, a combination of blue and one or a plurality of colors obtained from the group 3 arsenide semiconductor or the group 3 phosphide semiconductor
A light emitting device capable of multicolor emission can be obtained. Further, a common light emitting element made of a group 3 nitride semiconductor and a first light emitting element made of a group 3 arsenide semiconductor or a group 3 phosphide semiconductor on a layer made of a group 3 nitride semiconductor are commonly used. Since it is formed on the substrate or layer of the object semiconductor, a light emitting device capable of multicolor light emission can be obtained by combining blue and one color or a plurality of colors obtained from the group 3 arsenide semiconductor or the group 3 phosphide semiconductor. . Further, since the first light emitting element and the second light emitting element are formed by epitaxial growth on a common substrate or a common layer, many kinds of light emitting element chips are joined or many kinds of light emitting diodes are arranged. Since there is no need, it is possible to obtain a multicolored flat panel display device.

[0012]

First Embodiment In FIG. 1, a light emitting device 100 has a sapphire substrate 1, and a 500 Å AlN buffer layer 2 is formed on the sapphire substrate 1. On the buffer layer 2, a high carrier concentration n ⁺ layer 3 made of silicon-doped GaN with a film thickness of about 2.0 μm and an electron concentration of 2 × 10 ¹⁸ / cm ³ is provided in this order.
High carrier concentration n consisting of silicon-doped (Al _x2 Ga _1-x2 ) _y2 In _1-y2 N with a film thickness of approximately 2.0 μm and electron concentration of 2 × 10 ¹⁸ / cm ^3.
+ Layer 4, film thickness about 0.5 μm, light emitting layer 5 made of zinc (Zn) and silicon-doped (Al _x1 Ga _1-x1 ) _y1 In _1-y1 N, film thickness about 1.
A p-layer 6 made of magnesium-doped (Al _x2 Ga _1-x2 ) _y2 In _1-y2 N with a thickness of 0 μm and a hole concentration of 2 × 10 ¹⁷ / cm ³ is formed. Then, an electrode 7 made of nickel connected to the p layer 6 and an electrode 8 made of nickel connected to the high carrier concentration n ⁺ layer 4 are formed. The electrodes 7, 8, the p layer 6, the light emitting layer 5, and the n layer 4 constitute a first light emitting element.

On the other hand, on the high carrier concentration n ⁺ layer 3,
500 Å buffer layer 10 made of GaAs, the buffer layer 10
On top of the n-layer 11 made of Si-doped Al _z Ga _1-z As and having a thickness of about 1 μm, and on the n-layer 11 a p made of Zn-doped Al _z Ga _1-z As having a thickness of about 1 μm. Layer 12, Ni on the p-layer 12
The electrode 9 is formed. The electrodes 9, 8 and the p layer 12 and the n layer 11 constitute a second light emitting element.

Next, a method of manufacturing the light emitting device 100 having this structure will be described. The light emitting device 100 was manufactured by vapor phase epitaxy by an organometallic compound vapor phase epitaxy method (hereinafter referred to as “M0VPE”). The gas used was NH ₃ and carrier gas H ₂ or N ₂ , trimethylgallium (Ga (CH ₃ ) ₃ ) (hereinafter referred to as “TMG”) and trimethylaluminum (Al (CH ₃ ).
₃ ) (hereinafter referred to as “TMA”) and trimethylindium (In (C
H ₃₎ a ₃₎ (hereinafter referred to as "TMI") and silane (referred SiH ₄₎ and diethyl zinc (hereinafter "DEZ") and arsine (AsH ₃₎ and dimethyl zinc (hereinafter referred to as "DMZ").

First, the single-crystal sapphire substrate 1 whose main surface is the a-plane cleaned by organic cleaning and heat treatment is mounted on a susceptor placed in the reaction chamber of the M0VPE apparatus. Then, at a pressure of 1100 while flowing H ₂ into the reaction chamber at a flow rate of 2 liter / min under normal pressure
The sapphire substrate 1 was vapor-phase etched at 0 ° C.

Next, the temperature is lowered to 400 ° C. and H ₂ is added.
20 liter / min, NH ₃ 10 liter / min, TMA 1.8 × 10 ^-5
The buffer layer 2 of AlN was formed at a thickness of about 500Å by supplying at a mol / min. Next, the temperature of the sapphire substrate 1 is set to 1150.
℃ to retain a thickness of about 2.2 [mu] m, the electron concentration of 2 × 10 ¹⁸ / cm high carrier concentration of GaN silicon doped ³ n ⁺ layer 3
Was formed.

The composition ratio of the light emitting layer 5 (active layer) and the clad layers 4 and 6 in the case where the emission peak wavelength is set to 520 nm with zinc (Zn) and silicon (Si) as the emission centers in the first light emitting device. Examples of crystal growth conditions will be described. After forming the above-mentioned high carrier concentration n ⁺ layer 3, the temperature of the sapphire substrate 1 is maintained at 850 ° C. and N ₂ or H ₂ is adjusted to 10
liter / min, NH ₃ 10 liter / min, TMG 1.12 × 10 ^-4 mol / min, TMA 0.47 × 10 ^-4 mol / min, TMI 0.1 × 10 ^-4
Mol / min, and silane was introduced, and a film thickness of about 0.5 μm and a concentration of 1 × 10 ¹⁸ / cm ³ of silicon-doped (Al _0.47 Ga _0.53 ) _0.9 I
A high carrier concentration n ⁺ layer 4 of n _0.1 N was formed.

Subsequently, the temperature was maintained at 850 ° C. and N ₂ or H _{2 was} added.
20 liter / min, NH ₃ 10 liter / min, TMG 1.53 × 10
^-4 mol / min, TMA 0.47 × 10 ^-4 mol / min, TMI 0.02 ×
Introducing 10 ^-4 mol / min, 6 × 10 ^-7 mol / min of DEZ and 1 × 10 ^-8 mol / min of silane, and zinc (Zn) with a film thickness of about 0.5 μm
And a light emitting layer 5 made of (Al _0.3 Ga _0.7 ) _0.94 In _0.06 N doped with silicon (Si). Zinc (Z
n) concentration is 4 × 10 ¹⁹ / cm ³ , silicon (Si) concentration is 4 × 10
^{It is 19} / cm ³ .

Subsequently, the temperature was maintained at 1100 ° C. and N ₂ or H _{2 was} added.
20 liter / min, NH ₃ 10 liter / min, TMG 1.12 × 10
^-4 mol / min, TMA 0.47 × 10 ^-4 mol / min, TMI 0.1 ×
10 ^-4 mol / min, and, CP to ₂ Mg 2 × 10 ^-4 mol / min was introduced, a film thickness of about 1.0 [mu] m of magnesium (Mg) doped (Al
_A p-layer 6 made of _0.47 Ga _0.53 ) _0.9 In _0.1 N was formed. p
The magnesium concentration in layer 6 is 1 × 10 ²⁰ / cm ³ . In this state, the p layer 6 is still an insulator having a resistivity of 10 ⁸ Ωcm or more.

Next, the p-type layer 6 was uniformly irradiated with an electron beam by using a reflection electron beam diffractometer. The electron beam irradiation conditions are: accelerating voltage about 10KV, sample current 1μA, beam moving speed 0.2m
m / sec, beam diameter 60 μmφ, and vacuum degree 5.0 × 10 ⁻⁵ Torr. Due to this electron beam irradiation, the p-layer 6 has a hole concentration of 2
× 10 ¹⁷ / cm ^3, was a p conductivity type semiconductor resistivity 2Omucm.
In this way, a wafer having a multilayer structure was obtained.

Next, in the portion where the second light emitting element is formed,
The p layer 6, the light emitting layer 5, and the n layer 4 were removed by etching. Then, maintain the substrate temperature at 400 ° C and set TMG to 1.12 × 10
^The buffer layer 10 was formed by flowing AsH ₃ at ⁻⁴ mol / min and 5.6 × 10 ⁻³ mol / min. Next, the substrate temperature was raised to 700 ° C, TMG was 0.812 × 10 ^-4 mol / min, and TMA was 0.308 × 10 ^-4.
Mol / min, AsH ₃ 5.6 x 10 ^-3 mol / min, SiH ₄ 1.0 x 10
N layer 11 composed of n-type Al _0.4 Ga _0.6 As with a flow ^{rate of -6} mol / division 11
Was formed. Next, TMG was added at 0.812 × 10 ^-4 mol / min, TMA
0.308 × 10 ^-4 mol / min, AsH ₃ at 5.6 × 10 ^-4 mol / min,
DMZ was flowed at 2 × 10 ⁻⁶ mol / min to form a p-layer 12 made of p-type Al _0.4 Ga _0.6 As.

Next, an AuZn / Au electrode 9 is formed on the p layer, and a Ni electrode 7 and an electrode 8 are formed on the p layer 6 and the n ⁺ layer 3 to form Al.
A second light emitting device composed of a GaAs pn junction was formed. In this way, blue light is emitted from the first light emitting element and red light is obtained from the second light emitting element.

In the above embodiment, the n ⁺ layer 3 and the p layer 12 of AlGaAs may be formed after the surface of the n ⁺ layer 3 is surface-treated with arsenic instead of the GaAs buffer layer 10.

The light emitting device 200 of the second embodiment may be constructed as shown in FIG. The same numbers are given to the layers having the same functions as those in the first embodiment. On the sapphire substrate 1, a buffer layer 2 made of AlN and an n ⁺ layer 3 made of GaN are formed. That n ⁺
On the layer 3, as a first light emitting element, (Al _0.47 Ga _0.53 ).
High carrier concentration n ⁺ layer 4 consisting of _0.9 In _0.1 N, zinc (Zn)
And a light emitting layer 5 composed of silicon (Si) -doped (Al _0.3 Ga _0.7 ) _0.94 In _0.06 N, and magnesium (Mg) -doped (Al _0.47 Ga
_A p-layer 6 made of _0.53 ) _0.9 In _0.1 N is formed. The light emitting layer 5 and the p layer 6 are made p-type by heat treatment in a nitrogen atmosphere.

On the p-layer 6, a buffer layer 10 made of GaAs and n-type Al _0.4 Ga _0.6 As are provided as a second light emitting element.
N layer 11 made of p-type Al, p layer 1 made of p-type Al _0.4 Ga _0.6 As
2 is formed. Then, an AuZn / Au electrode 9 is formed on the p layer 12, an Ni / AuGe / Ni / Au electrode 8a is formed on the n layer 11, and a Ni electrode 7 and an electrode 8b are formed on the p layer 6 and the n ⁺ layer 3. There is. With such a structure, a light emitting device in which the first light emitting element made of a group 3 nitride semiconductor and the second light emitting element made of a group 3 arsenide semiconductor are formed in the same group 3 nitride semiconductor layer can be obtained. .

In the above embodiment, the p layer 6 is made of GaN.
The light emitting layer 5 may be Ga _0.94 In _0.06 N and the n layer 4 may be GaN. Further, in the above-described embodiment, the GaP buffer layer is used in place of the GaAs buffer layer, and the GaP layer is used in place of the AlGaAs layer. Then, the second light emitting element including the group III phosphide semiconductor layer may be formed in the same group III nitride semiconductor layer. Further, a layer made of a group 3 arsenide and a layer made of a group 3 phosphide may be sequentially stacked on the layer made of a group 3 nitride semiconductor layer, or may be laminated at different portions.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a configuration of a light emitting device according to a first specific example of the present invention.

FIG. 2 is a configuration diagram showing a configuration of a light emitting device according to a second embodiment of the invention.

[Explanation of symbols]

100, 200 ... Light emitting device 1 ... Sapphire substrate 2 ... Buffer layer 3 ... High carrier concentration n ⁺ layer 4 ... High carrier concentration n ⁺ layer 5 ... Light emitting layer 6 ... P layer 10 ... Buffer layer 11 ... N layer 12 ... P layer 7, 8, 9 ... Electrodes

Front page continued (72) Inventor Norikatsu Koide 1 Nagachibata, Ochiai, Kasuga-cho, Nishikasugai-gun, Aichi Prefecture Toyota Gosei Co., Ltd. No. 1 Toyota Central Research Institute Co., Ltd. (72) Inventor Toru Kaji 41 Nagamichi, Nagakute Town, Aichi-gun, Aichi Prefecture

Claims (6)

[Claims] 1. A Group III nitride semiconductor (Al _x Ga _Y In _1-XY N; X = 0,
Y = 0, X = Y = 0 is included), and a semiconductor device having a layer consisting of
A layer composed of at least a group 3 arsenide semiconductor formed by epitaxial growth on a group 3 nitride semiconductor layer;
Alternatively, a semiconductor device having one or a plurality of semiconductor elements having a layer made of a Group 3 phosphide semiconductor. 2. A group III nitride semiconductor (Al _x Ga _Y In _1-XY N; X = 0,
(Including Y = 0, X = Y = 0) n layer showing n conductivity type, and p
A first light emitting device having a p-type layer showing a conductivity type; an n-layer made of a Group 3 arsenide semiconductor or a Group 3 phosphide semiconductor formed by epitaxial growth on a Group 3 nitride semiconductor layer; and a p-layer. A second light emitting element having the light emitting device. 3. The first light emitting device comprises an n layer, a p layer, and
3. The light emitting device according to claim 2, wherein the light emitting layer interposed therebetween has a three-layer structure formed by a double heterojunction in which a semiconductor having a narrow band gap is sandwiched by semiconductors having a wide band gap. 4. The second light emitting device is GaAs or AlGa
The light emitting device according to claim 2, wherein the light emitting device comprises As. 5. The light emitting device according to claim 2, wherein the second light emitting element is an element formed after arsenicizing or phosphating the surface of the layer of the group III nitride semiconductor. 6. A compound semiconductor of an element forming the group III nitride semiconductor and an element forming the second light emitting element is provided between the second light emitting element and the group III nitride semiconductor. The light emitting device according to claim 2, wherein a buffer layer is formed.