Nitride-compound semiconductor device

• US 6,316,785 B1
• Filed: 10/14/1999
• Issued: 11/13/2001
• Est. Priority Date: 10/15/1998
• Status: Expired due to Term

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Nunoue, Shinya, Yamamoto, Masahiro
• Primary Examiner(s): Tran, Minh Loan
• Application Number:
  US09/418,025
• Time in Patent Office: 761 Days
• Field of Search: 257/13, 257/14, 257/22, 257/94, 257/96, 257/103, 257/190, 257/98, 372/43-46
• US Class Current: 257/14
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: H01L 33/007 comprising nitride compounds
• CPC Class Codes: H01L 33/32 containing nitrogen
• CPC Class Codes: H01S 2301/173 The laser chip comprising special buffer layers, e.g. dislocation prevention or reduction
• CPC Class Codes: H01S 2304/04 MOCVD or MOVPE
• CPC Class Codes: H01S 2304/12 Pendeo epitaxial lateral overgrowth [ELOG], e.g. for growing GaN based blue laser diodes
• CPC Class Codes: H01S 5/0213 Sapphire, quartz or diamond based substrates
• CPC Class Codes: H01S 5/04257 having positive and negative electrodes on the same side of the substrate
• CPC Class Codes: H01S 5/2201 in a specific crystallographic orientation
• CPC Class Codes: H01S 5/2231 with inner confining structure only between the active layer and the upper electrode
• CPC Class Codes: H01S 5/3072 Diffusion blocking layer, i.e. a special layer blocking diffusion of dopants
• CPC Class Codes: H01S 5/320225 polar orientation
• CPC Class Codes: H01S 5/34333 with a well layer based on Ga(In)N or Ga(In)P, e.g. blue laser

Abstract

A GaAlInBN systems semiconductor device is spaced apart from a substrate by a layer for reducing the propagation of a dislocation. This layer has a protrusion or protrusions, each having sidewalls on which a single crystal is exposed.

Claims

1. A nitride-compound semiconductor device comprising:

a substrate having a top surface;

a first layer disposed on said top surface of said substrate, said first layer formed from the materials represented as Al_xGa_yIn_zB<sub>1−

(x+y+z)</sub>N where 0≦

x,y,z and x+y+z≦

1;

a second layer disposed on said first layer, said second layer formed from the materials represented as Al_uGa_vIn_wB<sub>1−

(u+v+w)</sub>N where 0≦

u,v,w and u+v+w≦

1; and

a semiconductor element disposed on said second layer;

wherein said first layer and said second layer form an interface having a plurality of protrusions, and where a side wall, a top surface, and a bottom surface of each protrusion is a single crystal.

2. The nitride-compound semiconductor device according to claim 1, wherein said semiconductor element is a nitride-compound semiconductor light emitting device.

3. The nitride-compound semiconductor device according to claim 2, wherein said nitride-compound semiconductor light emitting device comprises:

an n-GaAIN clad layer;

an InGaN active layer disposed on said n-GaAIN clad layer; and

a p-GaAIN clad layer disposed on said InGaN active layer.

4. The nitride-compound semiconductor device according to claim 3, wherein said p-GaAIN clad layer is a mesa-shaped structure with a top portion and further comprises:

an n-type InGaN light absorbing layer formed on said p-GaAIN clad layer other than at the top portion of said mesa structure; and

a p-type GaN contact layer formed on said n-type InGaN light absorbing layer and on said top portion of said mesa shaped structure.

5. The nitride-compound semiconductor device according to claim 1, wherein said plurality of protrusions are configured in a repeating pattern.

6. The nitride-compound semiconductor device according to claim 1, wherein each of said plurality of protrusions have a height d1 of 0.1 to two microns and a width W2 of at least one micron at its top;

and

wherein every two adjoining protrusions have a distance W1 of one to 10 microns therebetween.

7. A nitride-compound semiconductor device comprising:

a substrate having a top surface;

at least one structure disposed on the top surface of the substrate and having a single crystal side wall, said structure being formed from the materials represented as Al_xGa_yIn_zB<sub>1−

(x+y+z)</sub>N where 0≦

x,y,z and x+y+z≦

1;

a layer disposed on said structure, said layer being formed from the materials represented as Al_uGa_vIn_wB<sub>1−

(u+v+w)</sub>N where 0≦

u,v,w and u+v+w≦

1; and

a semiconductor element disposed on said layer;

wherein said structure has a plurality of protrusions, each having a height d1 of 0.1 to two microns and a width W2 of at least one micron at its top, every two adjoining protrusions having a distance W1 of one to 10 microns therebetween.

8. A nitride-compound semiconductor device comprising:

a substrate having a top surface;

a layer disposed on said top surface of said substrate, said layer having a lower and an upper portion having a boundary therebetween on which a plurality of protrusions are disposed, each protrusion having a sidewall which is a single crystal, said lower and said upper portion being formed from the materials represented as Al_xGa_yIn_zB<sub>1−

(x+y+z)</sub>N where 0≦

x,y,z and x+y+z≦

1, and Al_uGa_vIn_wB<sub>1−

(u+v+w)</sub>N where 0≦

u,v,w and u+v+w≦

1, respectively; and

a semiconductor element disposed on said layer;

wherein said protrusion having a height d1 of 0.1 to two microns and a width W2 of at least one micron at its top, every two adjoining protrusions having a distance W1 of one to 10 microns therebetween.

9. A nitride-compound semiconductor device comprising:

a substrate having a top surface;

a first layer disposed on the top surface of said substrate, said first layer formed from the materials represented as Al_xGa_yIn_zB<sub>1−

(x+y+z)</sub>N where 0≦

x,y,z and x+y+z≦

1, said first layer having a plurality of dislocations oriented in a direction perpendicular to said top surface of said substrate;

a second layer disposed on said first layer, said second layer formed from the materials represented as Al_uGa_vIn_wB<sub>1−

(u+v+w)</sub>N where 0≦

u,v,w and u+v+w≦

1, said second layer having a plurality of dislocations oriented lateral to said top surface of said substrate; and

a semiconductor element disposed on said second layer;

wherein said first layer and said second layer form an interface having a plurality of protrusions, and where a side wall, a top surface, and a bottom surface of each protrusion is a single crystal.

10. The nitride-compound semiconductor device according to claim 9, wherein said semiconductor element comprises:

an n-GaAIN clad layer;

an InGaN active layer disposed on said n-GaAI N clad layer; and

a p-GaAIN clad layer disposed on said InGaN active layer.

11. The nitride-compound semiconductor device according to claim 10, wherein said p-GaAIN clad layer is a mesa-shaped structure with a top portion and further comprises:

an n-type InGaN light absorbing layer formed on said p-GaAIN clad layer other than at said top portion said mesa structure; and

a p-type GaN contact layer formed on said n-type InGaN light absorbing layer and on said top portion of said mesa-shaped structure.

12. The nitride-compound semiconductor device according to claim 9, wherein said plurality of protrusions are configured in a repeating pattern.

13. The nitride-compound semiconductor device according to claim 9,

wherein each of said plurality of protrusions have a height d1 of 0.1 to two microns arid a width W2 of at least one micron at its top;

and

wherein every two adjoining protrusions have a distance W1 of one to 10 microns therebetween.

14. A nitride-compound semiconductor device comprising:

a substrate having a top surface;

a first layer disposed on the top surface of said substrate, said first layer formed from the materials represented as Al_xGa_yIn_zB<sub>1−

(x+y+z)</sub>N where 0≦

x,y,z and x+y+z≦

1, said first layer having a plurality of dislocations oriented in a direction perpendicular to said top surface of said substrate;

a second layer disposed on said first layer, said second layer formed from the materials represented as Al_uGa_vIn_wB<sub>1−

(u+v+w)</sub>N where 0≦

u,v,w and u+v+w≦

1, said second layer having a plurality of dislocations oriented lateral to said top surface of said substrate; and

a semiconductor element disposed on said second layer;

wherein said first layer and said second layer form an interface having protrusions of which sidewall is a single crystal;

wherein said protrusions have a height d1 of 0.1 to two microns and a width W2 of at least one micron at its top, every two adjoining protrusions having a distance W1 of one to 10 microns therebetween.