JPH09289351A - Semiconductor light-emitting element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the contact resistance between a p-type contact layer and metal to lower the operating voltage of a laser by forming this contact layer in specified conduction that it is made of a p-type Ga1-x Inx N on a double-hetero structure made of a III-V compd. contg. N. SOLUTION: This element comprises a p-type and n-type AlGaN clad layers 3, 7 having sufficiently low resistivities and a p-type Ga1-x Inx N contact layer 8 (0<=x<=1). An ohmic contact of a contact resistance of 3×10<-3> Ω.cm<2> between the contact layer 8 and Ni 11 and that between an n-type SiC substrate 1 at the back side and Al 10 are realized. The contact resistance between the contact layer 8 and Ni 11 is reduced to 1/3 because the potential barrier of the valence band between the GaInN and Ni is low, The operating voltage of a laser also lowers to 1/3, compared with that of the prior art.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a compound containing N-containing III-
The present invention relates to a light emitting device made of a group V compound.

[0002]

2. Description of the Related Art As a key device for the next-generation high-density information processing technology, it is possible to shorten the wavelength of a laser.
-Group V compound semiconductors are receiving attention.

Conventionally, a structure shown in FIG. 13 is known as a laser structure composed of a III-V group compound semiconductor containing N. The cavity length of this structure is 1.5 mm, the stripe width is 0.03 mm, and the active layer has a double hetero structure that is a multiple quantum well structure. With this structure, the oscillation wavelength is 417 nm,
Room temperature pulse oscillation with a threshold voltage of 34 V, a threshold current of 2.0 A, a threshold current density of 4 kA / cm ² , and a duty of 0.1% has been realized (Shuji Nakamura et al.; Japa.
n Jounal of Applied Physics Vol.35 (1996) pp.L74 ー L7
6).

[0004]

A technique relating to a laser structure or a SEL structure composed of a III-V group compound semiconductor containing N has a contact resistance between a p-type contact layer and a metal of 10 ^-2 Ω.multidot. There is a problem that the operating voltage of the laser increases because of the large size of cm ² .

The present invention provides a semiconductor light emitting device which realizes a low resistance p-type ohmic contact and has a lower threshold voltage than that of a conventional N-containing III-V compound.

[0006]

The inventors of the present invention have proposed the following techniques (1) to (4) as techniques relating to a laser structure made of a III-V group compound containing N for solving the above problems. Devised.

(1) One or more layers having p-type conductivity or Ga having a continuously changed composition x on a double heterostructure composed of a III-V group compound containing N.
_A contact structure composed of _1-x In _x N (0 ≦ x ≦ 1) is manufactured. Thereby, the barrier height of the valence band with respect to a metal such as nickel can be reduced, the contact resistance between the p-type contact layer and the metal can be reduced, and the operating voltage of the laser is lowered. If the p-type contact layer has a property that the band edge energy of the valence band deviates from the vacuum level as the p-type contact layer moves away from the electrode metal, the barrier height of the valence band with respect to the metal such as nickel can be made smaller. ,
The operating voltage of the laser is even lower.

(2) One or more layers having p-type conductivity or Al having continuously changed composition x on a double heterostructure composed of a III-V group compound containing N.
_A contact structure composed of _1-x In _x N (0 ≦ x ≦ 1) is manufactured. Thereby, the barrier height of the valence band with respect to a metal such as nickel can be reduced, the contact resistance between the p-type contact layer and the metal can be reduced, and the operating voltage of the laser is lowered. If the p-type contact layer has a property that the band edge energy of the valence band deviates from the vacuum level as the p-type contact layer moves away from the electrode metal, the barrier height of the valence band with respect to the metal such as nickel can be made smaller. ,
The operating voltage of the laser is even lower. Also, Al
_1-x In _x N (0 ≦ x ≦ 1) can be obtained by appropriately selecting the composition x.
Since it can be lattice-matched with the cladding layer and the guide layer, a contact layer with few defects can be obtained.

(3) Consists of a III-V group compound containing N
Double heterostructure, especially p-type Al _yGa_1-yN (0 ≦ y
P on the double heterostructure having a cladding layer of ≦ 1)
One or more layers having compositional conductivity or composition x
Al continuously changed_xGa_1-xFrom N (0 ≦ x ≦ 1)
Producing a structured contact structure. As a result,
To reduce the barrier height of the valence band between metals such as ice ax
The contact resistance between the p-type contact layer and the metal.
The resistance can be reduced and the operating voltage of the laser is lowered. p-type computer
As the tact layer moves away from the electrode metal,
If the edge energy has the property of deviating from the vacuum level,
For example, the barrier height of the valence band between metal such as nickel
The operating voltage of the laser can be
It drops.

(4) One or more layers having p-type conductivity having a carrier density of at least 10 ¹⁸ cm ^-3 or a composition x on a double heterostructure composed of a III-V group compound containing N. Ga _1-x I with continuously changed
n _x N or Al _1-x In _x N or Al _x Ga _1-x N (0
A contact structure composed of ≤x≤1) is manufactured.
Thereby, the barrier height of the valence band with respect to a metal such as nickel can be reduced, the contact resistance between the p-type contact layer and the metal can be reduced, and the operating voltage of the laser is lowered. If the p-type contact layer has a property that the band edge energy of the valence band deviates from the vacuum level as the p-type contact layer moves away from the electrode metal, the barrier height of the valence band with respect to the metal such as nickel can be made smaller. , The operating voltage of the laser is even lower.

In the production of the light emitting device of the present invention, crystal growth is performed by the metal-organic vapor phase epitaxial growth method using the metal-organic vapor phase epitaxial apparatus shown in FIG. 7, and shown in FIG. It is done through the process of

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for manufacturing a semiconductor light emitting device and its characteristics according to the present invention will be described with reference to the drawings.

(Embodiment 1) First, an n-type SiC (0002) substrate 1 is first cleaned and pretreated with an organic solvent, placed on a carbon substrate holder 70, and placed in a metalorganic vapor phase epitaxial growth apparatus. throw into. n-type SiC (0
002) Cleaning and pretreatment of the substrate 1 with an organic solvent is a well-known method.

Next, the inside of the growth apparatus is filled with hydrogen at a pressure of 70 Torr, and the n-type SiC (0002) substrate 1 is put together with the carbon substrate holder 70 in a hydrogen atmosphere by a heater 77 at 1090.
℃, adsorbed gas and oxides adhering to the surface,
Remove water molecules, etc. After that, the temperature of the n-type SiC (0002) substrate 1 is lowered to 1000 ° C., the valves 72, 74 and 76 of the gas supply lines of trimethylaluminum, ammonia and silane are opened, and trimethylaluminum 5.
5 sccm, ammonia 2.5 l / min, silane 1
Flowing 2.5 sccm, the n-type AlN buffer layer 2 is 30
0Å Stack.

After stacking the n-type AlN buffer layer 2, n
The temperature of the type SiC (0002) substrate 1 is raised to 1030 ° C., and valves 71 and 7 of gas supply lines for trimethylgallium, trimethylaluminum, ammonia, and silane are supplied.
Open 2, 74, 76 and trimethylgallium 2.7sc
cm, trimethyl aluminum 8.7 sccm, ammonia 2.5 l / min, and silane 12.5 sccm are flown, and n-type Al _0.2 Ga _0.8 N 3 having a layer thickness of 1.5 μm is laminated.

After laminating n-type Al _0.2 Ga _0.8 N 3, a gas supply line 7 for trimethylaluminum and silane is provided.
2, 76 are closed, valves 71, 74 of the gas supply lines for trimethylgallium and ammonia are opened, 2.7 sccm of trimethylgallium and 2.5 l / min of ammonia are flown, and 1000 Å of undoped GaN light guide layer 4 is laminated.

After stacking the undoped GaN optical guide layer 4, the temperature of the n-type SiC (0002) substrate 1 is lowered to 680 ° C., the valves 71 and 73 of the gas supply lines of trimethylgallium and trimethylindium are opened, and the trimethylgallium 2 0.7 sccm, trimethylindium 27s
Ccm and 10 l / min of ammonia are made to flow, and an undoped Ga _0.9 In _0.1 N active layer 5 is laminated 100 Å.

Undoped Ga _0.9 In _0.1 N active layer # 1
After stacking 00Å, the temperature of the n-type SiC (0002) substrate 1 is raised to 1030 ° C., the gas supply line 73 of trimethylindium is closed, the valves 71 and 74 of the gas supply lines of trimethylgallium and ammonia are opened, and the trimethylgallium 2 0.7 sccm, ammonia 2.5 l / m
and the undoped GaN light guide layer 6 is
ÅLaminate.

The undoped GaN light guide layer 6 is set to 1000.
Å After stacking, valves 71, 72, 74, 75 of the gas supply lines for trimethylgallium, trimethylaluminum, ammonia, and cyclopentadienylmagnesium are opened, and trimethylgallium 2.7 sccm, trimethylaluminum 8.7 sccm, and ammonia 2.5 l / M
in, cyclopentadienyl magnesium 5.0 scc
flowing m, a p-type Al _{0. 2} Ga _0.8 N cladding layer 7 1.0
μm is laminated.

After laminating the p-type Al _0.2 Ga _0.8 N cladding layer 7, the valve 72 of the gas supply line for trimethylaluminum was closed, the temperature of the n-type SiC (0002) substrate 1 was lowered to 680 ° C., and trimethylgallium, trimethyl The valves 71, 73 and 75 of the gas supply lines for indium and cyclopentadienyl magnesium were opened to give 2.7 sccm of trimethylgallium and 27 of trimethylindium.
Sccm, 10 l / min of ammonia, 5.0 sccm of cyclopentadienyl magnesium are flown, and p-type Ga
_{A 0.9} In _0.1 N contact layer 8 is laminated in a thickness of 100 Å.

After that, only the valve of the hydrogen gas supply line was opened, and SiC was added in a hydrogen atmosphere at a pressure of 70 Torr.
The temperature of the (0002) substrate 1 is set to 700 ° C. and annealed for 1 hour to activate magnesium which is a p-type dopant. After the annealing is completed, the temperature of the SiC (0002) substrate 1 is returned to room temperature, and the SiC (0002) substrate 1
Is taken out of the MOCVD tool.

Next, with respect to the substrate 1 taken out of the metal-organic vapor phase epitaxial growth apparatus after completion of crystal growth,
A process for depositing Ni11 and Au12 will be described. First, the SiO ₂ film 9 having a thickness of 1000 Å was formed on the p-type Ga _0.9 In _0.1 N film.
It is attached on the entire surface of the contact layer 8. Next, resist 68
Is coated on the entire surface of the SiO ₂ film 9, and a mask 69 having a transparent striped portion having a width of 10 μm is covered, and light is applied from above the mask 69 to expose the resist 68 in the transparent striped portion. And removed to expose the SiO 2 film 9. Then, exposed SiO ₂ is removed in an aqueous solution of HF: NH ₄ F = 1: 10. After that, the resist 68 is dissolved in acetone, and the remaining resist 68 is removed in O ₂ plasma. Finally, p-type Ga _0.9 In _0.1 N contact layer 8 and SiO 2
₂ Ni11 and Au12 are vapor-deposited on the film 9. This process is well known in the art.

Finally, aluminum 10 is vapor-deposited on the back surface of the SiC substrate 2 and the substrate 2 is cleaved to a cavity length of 1 mm to complete the laser.

The characteristics of the laser of the present invention will be described below. First, the optical characteristics will be described. The oscillation wavelength of the laser is 410 nm. The reflectivity of the end face is 22% for both the front and rear. The internal loss of the laser is 5 cm ^-1 , and the loss in the resonator is 20 cm ^-1 .

Next, the electrical characteristics will be described. The current-voltage characteristic of the laser of the present invention is clearly improved over the conventional one. The carrier densities of the p-type and n-type Al _0.2 Ga _0.8 N cladding layers 3 and 7 are 1 × 10 ¹⁸ / cm ³ , respectively.
The carrier density of the p-type Ga _0.9 In _0.1 N contact layer 8 is 1 × 10 ¹⁸ / cm ³ , and the mobility is p-type and n-type Al _0.2 Ga.
_0.8 N cladding layer 3, 7, p-type Ga _0.9 In _0.1 N contact layer 8, respectively ^{10cm 2 / V · s, 250cm} 2 / V
· S, a 10cm ² / V · s, less p-type and n-type sufficiently resistivity Al _0.2 Ga _0.8 N cladding layer 3, 7, p-type Ga _0.9 In _0.1 N contact layer 8 is manufactured. In addition, p-type Ga _0.9 In _0.1 N contact layer 8 and nickel 1
1 has realized ohmic contact with a contact resistance of ³ × 10 ⁻³ Ω · cm ² , and also has realized ohmic contact between the rear surface n-type SiC substrate 1 and aluminum 10. p-type G
The contact resistance between the a _0.9 In _0.1 N contact layer 8 and nickel 11 is ⅓ of the contact resistance between the conventional p-type GaN contact layer 84 and nickel 85, which is Ga _0.9 In _0.1. The potential barrier in the valence band between N and nickel is 0.70 eV, and the potential barrier in the valence band between the conventional p-type GaN contact layer 84 and nickel 85 is 0.09 eV smaller than 0.79 eV. Because there is. The operating voltage of the laser is 10 V, which is 1/3 that of the conventional laser.

In place of the SiC substrate 1, Al ₂ O ₃ ,
Similar results can be obtained by using an oxide substrate such as ZnO or LiAlO ₂ . Further, similar results can be obtained by using an inclined SiC substrate.

(Embodiment 2) The steps from the cleaning and pretreatment with an organic solvent to the lamination of the p-type Al _0.2 Ga _0.8 N cladding layer 19 are the same as in Embodiment 1.

P-type Ga _0.9 In _0.1 N layer 20, p-type Ga
_0.8 In _0.2 N layer 21, p-type Ga _0.7 In _0.3 N layer 22 3
A procedure for manufacturing the p-type contact structure 23 including layers will be described. After laminating the p-type Al _0.2 Ga _0.8 N cladding layer 19, the valve 72 of the gas supply line of trimethylaluminum was closed, the temperature of the n-type SiC (0002) substrate 13 was lowered to 680 ° C., and trimethylgallium, trimethylindium, cyclo The valves 71, 73, and 75 of the pentadienyl magnesium gas supply line were opened, and trimethylgallium 2.7 sccm and trimethylindium 54 s
ccm, ammonia 10 l / min, cyclopentadienyl magnesium 5.0 sccm, p-type Ga _0.9
An In _0.1 N layer 20 is laminated in a thickness of 33 Å.

After stacking the p-type Ga _0.9 In _0.1 N layer 20, the temperature of the n-type SiC (0002) substrate # is lowered to 660 ° C. and trimethylgallium, trimethylindium,
The valves 71, 73, and 75 of the cyclopentadienyl magnesium gas supply line were opened, and trimethylgallium 2.7 sccm, trimethylindium 54 sccm,
Ammonia 10 l / min and cyclopentadienyl magnesium 5.0 sccm are flown, p-type Ga _0.8 In _0.2 N
The layer 21 is laminated by 33Å.

After laminating the p-type Ga _0.8 In _0.2 N layer 21, the temperature of the n-type SiC (0002) substrate # is lowered to 640 ° C., and trimethylgallium, trimethylindium,
The valves 71, 73, 75 of the cyclopentadienyl magnesium gas supply line were opened, and trimethylgallium 2.7 sccm, trimethylindium 81 sccm,
Ammonia 10 l / min and cyclopentadienyl magnesium 5.0 sccm are flown, p-type Ga _0.7 In _0.3 N
The layer 22 is laminated by 33Å.

Then, annealing is performed by the same method as in the first embodiment, a process is performed to deposit metal, and cleavage is performed to complete the laser.

The characteristics of the laser of the present invention will be described below. First, the optical characteristics will be described. The oscillation wavelength of the laser is 410 nm. The reflectivity of the end face is 22% for both the front and rear. The internal loss of the laser is 5 cm ^-1 , and the loss in the resonator is 20 cm ^-1 .

Next, the electrical characteristics will be described. The current-voltage characteristic of the laser of the present invention is clearly improved over the conventional one. The carrier density of the p-type and n-type Al _0.2 Ga _0.8 N cladding layers 15 and 19 is 1 × 10 ¹⁸ / cm ³ , and the carrier density of the p-type contact structure 23 is 1 × 10 ¹⁸ / cm 3.
^3. Mobility is p-type and n-type Al _0.2 Ga _0.8 N cladding layers 15 and 19, p-type contact structure 23 10 cm each
² / V · s, 250 cm ² / V · s, 10 cm ² / V · s
And the p-type and n-type cladding layers 1 having sufficiently low resistivity
5, 19, p-type contact structure 23 has been manufactured.
Further, an ohmic contact with a contact resistance of 1 × 10 ⁻³ Ω · cm ² is realized between the p-type contact structure 23 and nickel 26,
Further, ohmic contact is also realized between the n-type SiC substrate 13 on the back surface and the aluminum 25. The contact resistance between the p-type contact structure 23 and nickel 26 is 1/10 of the contact resistance between the conventional p-type GaN contact layer 84 and nickel 85, which is Ga _0.7 In _0.3 N 2.
And the conventional p-type GaN contact layer 84 with a potential barrier of 0.52 eV in the valence band between 2 and nickel 26.
This is because the potential barrier in the valence band between the nickel and the nickel 85 is 0.27 eV smaller than 0.79 eV. The operating voltage of the laser is 5V, which is one of that of conventional lasers.
It becomes / 6.

In place of the SiC substrate #, Al ₂ O ₃ ,
Similar results can be obtained by using an oxide substrate such as ZnO or LiAlO ₂ . Further, similar results can be obtained by using an inclined SiC substrate.

(Embodiment 3) The steps from washing and pretreatment with an organic solvent to stacking of p-type Al _0.2 Ga _0.8 N cladding layer # are the same as in Embodiment 1.

After stacking the p-type Al _0.2 Ga _0.8 N cladding layer 34, the valve 71 of the gas supply line for trimethylgallium is closed, the temperature of the n-type SiC (0002) substrate 28 is lowered to 680 ° C., and trimethylaluminum, trimethyl The valves 72, 73, and 75 of the gas supply lines for indium and cyclopentadienyl magnesium were opened, and 10 sccm of trimethylaluminum, 27 sccm of trimethylindium, 10 l / min of ammonia, and 5.0 sccm of cyclopentadienyl magnesium were flown, and p-type Al _0.7 In _{A 0.3N} contact layer 35 is laminated to 100 Å.

Then, annealing is performed by the same method as in the first embodiment, a process is performed to deposit metal, and cleavage is performed to complete the laser.

The characteristics of the laser of the present invention will be described below. First, the optical characteristics will be described. The oscillation wavelength of the laser is 410 nm. The reflectivity of the end face is 22% for both the front and rear. The internal loss of the laser is 5 cm ^-1 , and the loss in the resonator is 20 cm ^-1 .

Next, the electrical characteristics will be described. Of the present invention
The current-voltage characteristics of the laser are clearly better than the conventional one.
It is above. p-type and n-type Al_0.2Ga_0.8N clad layer
Carrier density of 30 and 34 is 1 × 10¹⁸/ Cm^Three, P-type
Al_0.7In_0.3The carrier density of the N contact layer 35 is 1
× 10¹⁸/ Cm^Three, Mobility is p-type and n-type Al_0.2Ga
_0.8N cladding layers 30, 34, p-type Al_0.7In_0.3N
Contact layer 35 10 cm each^Two/ Vs, 250c
m^Two/ V · s, 10 cm^Two/ V · s, which has a sufficient resistivity
Small p-type and n-type cladding layers 30, 34, p-type Al
_0.7In_0.3The N contact layer 35 is manufactured. Ma
P-type Al_0.7In_0.3N contact layer 35 and nickel
Contact resistance between 38 and 3X10^-3Ω · cm^TwoOhm sex
Touch, and the n-type SiC substrate 28 and aluminum on the back surface
An ohmic contact is also realized with the N-37. p
Type Al_0.7In_0.3N contact layer 35 and nickel 38
The contact resistance between them is the same as that of the conventional p-type GaN contact layer 84.
It is 1/3 of the contact resistance between nickel 85,
This is p-type Al_0.7In_0.3N contact layer 35 and nickel
And the potential barrier of the valence band between the
0 eV and conventional p-type GaN contact layer 84 and nickel
The potential barrier in the valence band between 85 and 0.79e
This is because it is smaller than V by 0.09 eV. Les
The operating voltage of the laser is 10V, which is 1/3 of the conventional laser.
You. Also, Al_0.7In_0.3N is more Si than conventional GaN
Since the lattice irregularity ratio with respect to the C substrate is small,
The p-type contact layer has fewer crystal defects than before.
Will be

In place of the SiC substrate 28, Al
Similar results can be obtained by using an oxide substrate such as ₂ O ₃ , ZnO or LiAlO ₂ . Further, similar results can be obtained by using an inclined SiC substrate.

(Embodiment 4) The steps from the cleaning and pretreatment with an organic solvent to the lamination of the p-type Al _0.2 Ga _0.8 N cladding layer # are the same as in Embodiment 1.

Next, the p-type Al _0.1 Ga _0.1 N layer 47 and the p-type G are formed.
A procedure for manufacturing the p-type contact structure 49 including two layers of the a _0.9 In _0.1 N layer 48 will be described.

After laminating the p-type Al _0.2 Ga _0.8 N cladding layer 46, the valves 72, 71 and 75 of the gas supply lines for trimethylaluminum, trimethylgallium, and cyclopentadienylmagnesium are opened, and 4.1 sccm of trimethylaluminum and trimethylaluminum are added. Gallium 2.7sc
cm, ammonia 10 l / min, cyclopentadienyl magnesium 5.0 sccm, p-type Al _0.1 G
a _0.9 N layer 47 is laminated 50 Å.

After stacking the p-type Al _0.1 Ga _0.9 N layer 47, the valve 72 of the gas supply line of trimethylaluminum is closed, and the valves 71, 73 of the gas supply line of trimethylgallium, trimethylindium and cyclopentadienylmagnesium, 75 is opened, the temperature of the substrate 40 is set to 680 ° C., and trimethylgallium 2.7 scc
m, trimethylindium 27 sccm, ammonia 1
0 l / min, cyclopentadienyl magnesium 5.
Flowing 0 sccm, the p-type Ga _0.9 In _0.1 N layer 48 becomes 50
ÅLaminate.

After that, annealing is performed by the same method as in the first embodiment, a process is performed to deposit metal, and cleavage is performed to complete the laser.

The characteristics of the laser of the present invention will be described below.
You. First, the optical characteristics will be described. Laser oscillation wavelength
Is 410 nm. The reflectivity of the end face is
Is also 22%. Laser # has an internal loss of 5 cm ^-1,
20 cm loss in resonator^-1It is.

Next, the electrical characteristics will be described. The current-voltage characteristic of the laser of the present invention is clearly improved over the conventional one. The p-type and n-type Al _0.2 Ga _0.8 N cladding layers 42 and 46 have a carrier density of 1 × 10 ¹⁸ / cm ³ , and the p-type contact structure 49 has a carrier density of 1 × 10 ¹⁸ / cm 3.
³ , p-type and n-type Al _0.2 Ga _0.8 N cladding layers 42 and 46, p-type contact structure 49 10 cm each
² / V · s, 250 cm ² / V · s, 10 cm ² / V · s
And the p-type and n-type cladding layers 4 having sufficiently low resistivity
2, 46, p-type contact structures 49 have been manufactured.
Further, an ohmic contact with a contact resistance of 2 × 10 ⁻³ Ω · cm ² is realized between the p-type contact structure 49 and the nickel 52,
Further, ohmic contact is also realized between the n-type SiC substrate 40 on the back surface and the aluminum 51. The contact resistance between the p-type contact structure 49 and nickel 52 is ⅕ of the contact resistance between the conventional p-type GaN contact layer 84 and nickel 85, which is p-type Ga _0.9 In _0.1 N.
The valence band potential barrier between the layer 48 and nickel 52 is 0.70 eV, and the valence band potential barrier between the conventional p-type GaN contact layer 84 and nickel 85 is 0.09 eV smaller than 0.79 eV. This is because the potential barrier is lowered between the p-type Al _0.1 Ga _0.1 N layer 47 and the p-type Ga _0.9 In _0.1 N layer 48. Operating voltage of laser is 8
V, which is 1/4 of the conventional laser.

In place of the SiC substrate 40, Al
Similar results can be obtained by using an oxide substrate such as ₂ O ₃ , ZnO or LiAlO ₂ . Further, similar results can be obtained by using an inclined SiC substrate.

(Embodiment 5) The steps from cleaning and pretreatment with an organic solvent to stacking of p-type Al _0.2 Ga _0.8 N cladding layer # are the same as in Embodiment 1.

Next, the p-type Al _0.7 In _0.3 N layer 61 and the p-type G are formed.
A manufacturing procedure of the p-type contact structure 63 including two layers of the a _0.9 In _0.1 N layer 62 will be described.

After stacking the p-type Al _0.2 Ga _0.8 N cladding layer 60, the valve 71 of the gas supply line for trimethylgallium was closed, the temperature of the n-type SiC (0002) substrate 54 was lowered to 680 ° C., and trimethylaluminum, trimethyl The valves 72, 73, and 75 of the gas supply lines for indium and cyclopentadienyl magnesium were opened, and 10 sccm of trimethylaluminum, 27 sccm of trimethylindium, 10 l / min of ammonia, and 5.0 sccm of cyclopentadienyl magnesium were flown, and p-type Al _0.7 In _0.3 N layer 61 is laminated 50 Å.

After laminating the p-type Al _0.7 In _0.3 N layer 61, the valve 72 of the gas supply line of trimethylaluminum is closed, and the valves 71, 73 of the gas supply line of trimethylgallium, trimethylindium and cyclopentadienylmagnesium, 75 is opened, the temperature of the substrate 40 is set to 680 ° C., and trimethylgallium 2.7 scc
m, trimethylindium 27 sccm, ammonia 1
0 l / min, cyclopentadienyl magnesium 5.
Flowing 0 sccm, the p-type Ga _0.9 In _0.1 N layer 62 becomes 50
ÅLaminate.

After that, annealing is performed in the same manner as in the first embodiment, a process is performed to deposit metal, and cleavage is performed to complete the laser.

The characteristics of the laser of the present invention will be described below. First, the optical characteristics will be described. The oscillation wavelength of the laser is 410 nm. The reflectivity of the end face is 22% for both the front and rear. The internal loss of the laser is 5 cm ^-1 , and the loss in the resonator is 20 cm ^-1 .

Next, the electrical characteristics will be described. The current-voltage characteristic of the laser of the present invention is clearly improved over the conventional one. The p-type and n-type Al _0.2 Ga _0.8 N cladding layers 56 and 60 have a carrier density of 1 × 10 ¹⁸ / cm ³ , and the p-type contact structure 63 has a carrier density of 6 × 10 ¹⁸ / cm 3.
³ , p-type and n-type Al _0.2 Ga _0.8 N cladding layers 56 and 60, p-type contact structure 63 10 cm each
² / V · s, 250 cm ² / V · s, 5 cm ² / V · s, and p-type and n-type clad layers 5 having sufficiently low resistivity
6, 60, p-type contact structures 63 have been manufactured.
Further, an ohmic contact with a contact resistance of 2 × 10 ⁻³ Ω · cm ² is realized between the p-type contact structure 63 and nickel 66,
Further, ohmic contact is realized also between the n-type SiC substrate 54 on the back surface and the aluminum 65. The contact resistance between the p-type contact structure 63 and nickel 66 is ⅕ of the contact resistance between the conventional p-type GaN contact layer 84 and nickel 85, which is p-type Ga _0.9 In _0.1 N.
The valence band potential barrier between the layer 62 and nickel 66 is 0.70 eV, and the valence band potential barrier between the conventional p-type GaN contact layer 84 and nickel 85 is 0.09 eV smaller than 0.79 eV. This is because the potential barrier is lowered between the p-type Al _0.7 In _0.3 N layer 61 and the p-type Ga _0.9 In _0.1 N layer 62. In addition, Al _0.7 In _0.3
Since N has a smaller lattice mismatch with respect to the SiC substrate than conventional GaN, the p-type contact layer in this embodiment has fewer crystal defects than the conventional one. The operating voltage of the laser is 8V, which is ¼ that of the conventional laser.

In place of the SiC substrate 54, Al
Similar results can be obtained by using an oxide substrate such as ₂ O ₃ , ZnO or LiAlO ₂ . Further, similar results can be obtained by using an inclined SiC substrate.

[0057]

Industrial Applicability The p-type contact layer manufactured by the above method realizes a lower threshold voltage of a semiconductor light emitting device and has better characteristics than conventional III-V containing N.
A group semiconductor laser is obtained.

[Brief description of drawings]

FIG. 1 is a structural sectional view of a semiconductor light emitting device according to a first embodiment of the present invention.

FIG. 2 is a structural sectional view of a semiconductor light emitting device according to a second embodiment of the present invention;

FIG. 3 is a structural cross-sectional view of a semiconductor light emitting device according to a third embodiment of the present invention.

FIG. 4 is a structural cross-sectional view of a semiconductor light emitting device according to a fourth embodiment of the present invention.

FIG. 5 is a structural cross-sectional view of a semiconductor light emitting device according to a fifth embodiment of the present invention.

FIG. 6 is a diagram relating to a process of the semiconductor light emitting device according to the first embodiment of the present invention.

FIG. 7 is a schematic view of an organic vapor phase metal epitaxial growth apparatus for manufacturing the semiconductor light emitting device of the present invention.

FIG. 8 is a diagram comparing current-voltage characteristics of a laser according to the first embodiment of the present invention with current-voltage characteristics of a conventional laser.

FIG. 9 is a diagram comparing current-voltage characteristics of a laser according to the second embodiment of the present invention with current-voltage characteristics of a conventional laser.

FIG. 10 shows current-voltage characteristics of a laser according to a third embodiment of the present invention and current of a conventional laser-
Figure comparing voltage characteristics

FIG. 11 shows current-voltage characteristics of the laser according to the fourth embodiment of the present invention and current of the conventional laser-
Figure comparing voltage characteristics

FIG. 12 shows current-voltage characteristics of a laser according to a fifth embodiment of the present invention and current of a conventional laser-
Figure comparing voltage characteristics

FIG. 13 is a diagram showing a relationship between a band gap and a lattice constant of a III-V group compound semiconductor, and a lattice constant of a substrate which is often used.

FIG. 14 is a structural cross-sectional view of a conventional semiconductor light emitting device.

[Explanation of symbols]

8 p-type Ga _0.9 In _0.1 N contact layer 11 Ni 12 Au 20 p-type Ga _0.9 In _0.1 N layer 21 p-type Ga _0.8 In _0.2 N layer 22 p-type Ga _0.7 In _0.3 N layer 23 p-type contact structure 26 Ni 27 Au 35 p-type Al _0.7 In _0.3 N contact layer 38 Ni 39 Au 47 p-type Al _0.2 Ga _0.8 N layer 48 p-type Ga _0.9 In _0.1 N layer 49 p-type contact structure 52 Ni 53 Au 61 p-type Al _0.7 In _0.3 N layer 62 p-type Ga _0.9 In _0.1 N layer 63 p-type contact structure 66 Ni 67 Au 84 p-type GaN contact layer 85 Ni 86 Au

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yusaburo Ban, 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Hidemi Takeishi, 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd.

Claims (21)

[Claims] 1. A sapphire substrate, a double hetero structure composed of a III-V group compound containing N, laminated on the sapphire substrate, and p-type conductivity laminated on the double hetero structure. , Ga _1-x In _x N (0 ≦ x ≦
A semiconductor light emitting device having a contact structure composed of 1). 2. A sapphire substrate, a double heterostructure composed of a III-V group compound containing N, laminated on the sapphire substrate, and p-type conductivity laminated on the double heterostructure. , A finite number of layers, each layer having a different composition Ga _{1 -x} In _x N (0 ≦ x ≦ 1)
A semiconductor light emitting device having a contact structure composed of: 3. A sapphire substrate, a double hetero structure composed of a III-V group compound containing N, laminated on the sapphire substrate, and having p-type conductivity laminated on the double hetero structure. , G whose composition changes continuously
A semiconductor light emitting device having a contact structure composed of a _1-x In _x N (0 ≦ x ≦ 1). 4. A sapphire substrate, a double heterostructure composed of a III-V group compound containing N and laminated on the sapphire substrate, and p-type conductivity laminated on the double heterostructure. , Al _1-x In _x N (0 ≦ x ≦
A semiconductor light emitting device having a contact structure composed of 1). 5. A sapphire substrate, a double heterostructure composed of a III-V group compound containing N and laminated on the sapphire substrate, and p-type conductivity laminated on the double heterostructure. , A finite number of layers, each layer having a different composition, Al _1-x In _x N (0 ≦ x ≦ 1)
A semiconductor light emitting device having a contact structure composed of: 6. A sapphire substrate, a double heterostructure composed of a III-V group compound containing N, laminated on the sapphire substrate, and having p-type conductivity laminated on the double heterostructure. , The composition changes continuously A
A semiconductor light emitting device having a contact structure composed of l _1-x In _x N (0 ≦ x ≦ 1). 7. A sapphire substrate and a III-V group compound containing N, which is laminated on the sapphire substrate,
And a double heterostructure including at least one layer containing Al in a layer having p-type conductivity, and Al _x Ga _1-x having p-type conductivity stacked on the double heterostructure.
A semiconductor light-emitting device having a contact structure composed of N (0 ≦ x ≦ 1). 8. A sapphire substrate and a III-V group compound containing N, which is laminated on the sapphire substrate,
And a double heterostructure including at least one layer containing Al in a layer having p-type conductivity and a finite number of layers having p-type conductivity stacked on the double heterostructure. _X Ga _1-x N with different compositions
A semiconductor light emitting device having a contact structure composed of (0 ≦ x ≦ 1). 9. A sapphire substrate, and a III-V group compound containing N, which is laminated on the sapphire substrate,
And a double hetero structure including at least one layer containing Al in a layer having p-type conductivity, and Al having p-type conductivity laminated on the double hetero structure and having a continuously changing composition. A semiconductor light emitting device having a contact structure composed of _x Ga _1-x N (0 ≦ x ≦ 1). 10. A sapphire substrate, a double hetero structure composed of a III-V group compound containing N and laminated on the sapphire substrate, and p-type conductivity laminated on the double hetero structure. And having a contact structure composed of Ga _{1 -x} In _x N (0 ≦ x ≦ 1) in which the composition of each layer is different, at least one layer having a carrier density of at least 10 ¹⁸ cm ^−3. Semiconductor light emitting device. 11. SiC, S instead of a sapphire substrate
The semiconductor light emitting device according to claim 1, wherein an i, ZnO or oxide substrate is used. 12. A contact structure having (GaN) _m (In
N) _n (m, n is a natural number) is comprised, The semiconductor light-emitting device in any one of Claims 1-10 characterized by the above-mentioned. 13. The semiconductor light emitting device according to claim 2, wherein the band edge energy of the valence band has a property of deviating from the vacuum level as the distance from the electrode metal increases. 14. The layer having n-type conductivity includes at least one layer containing Al.
The semiconductor light emitting device according to any one of the above. 15. A layer having p-type or n-type conductivity
11. The semiconductor light emitting device according to claim 10, which has a double hetero structure including at least one layer containing l. 16. An OFF substrate of SiC and O of the SiC.
Group III-V compound containing N stacked on FF substrate
A double heterostructure consisting of
It has p-type conductivity and has a carrier density of
At least 10 ¹⁸cm^-3Having at least one layer,
Ga composition of each layer is different_1-xIn_xN (0 ≦ x ≦
Characterized by having a contact structure composed of 1)
Semiconductor light emitting device. 17. The semiconductor according to claim 16, wherein Al _1-x In _x N (0 ≦ x ≦ 1) is used instead of Ga _1-x In _x N (0 ≦ x ≦ 1). Light emitting element. 18. The semiconductor light emitting device according to claim 16, wherein the composition of Ga _1-x In _x N (0 ≦ x ≦ 1) continuously changes. 19. The semiconductor light emitting device according to claim 17, wherein the composition of said Al _1-x In _x N (0 ≦ x ≦ 1) continuously changes. 20. The semiconductor light emitting device according to claim 16, wherein the band edge energy of the valence band has a property of deviating from the vacuum level as the distance from the electrode metal increases. 21. A layer having p-type or n-type conductivity
18. The semiconductor light emitting device according to claim 16 or 17, which has a double hetero structure including at least one layer containing l.