Nitride-based semiconductor device and manufacturing method thereof

• US 20010035531A1
• Filed: 03/21/2001
• Published: 11/01/2001
• Est. Priority Date: 03/24/2000
• Status: Active Grant

• Current Assignee: Epistar Corporation
• Original Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Inventors: Kano, Takashi, Ohbo, Hiroki
• Granted Patent: US 6,566,677 B2
• Time in Patent Office: Days
• US Class Current: 257/96
• CPC Class Codes: H01L 21/0242 Crystalline insulating materials
• CPC Class Codes: H01L 21/02458 Nitrides
• CPC Class Codes: H01L 21/02507 Alternating layers, e.g. superlattice
• CPC Class Codes: H01L 21/0254 Nitrides
• CPC Class Codes: H01L 33/0066 with a substrate not being a III-V compound
• 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 5/0213 Sapphire, quartz or diamond based substrates
• CPC Class Codes: H01S 5/2009 by using electron barrier layers
• CPC Class Codes: H01S 5/3201 incorporating bulkstrain effects, e.g. strain compensation, strain related to polarisation
• CPC Class Codes: H01S 5/3216 quantum well or superlattice cladding layers
• CPC Class Codes: H01S 5/32341 blue laser based on GaN or GaP

Abstract

In the manufacture of a semiconductor laser device, sequentially grown on a sapphire substrate in the following order are a buffer layer, a first undoped GaN layer, a first super lattice defect reducing layer, a second undoped GaN layer, a second super lattice defect reducing layer, a third undoped GaN layer, a third super lattice defect reducing layer and a fourth undoped GaN layer. A device structure is then formed thereon. The first to third super lattice defect reducing layers each include five pairs of InGaN and AlGaN films alternately placed on one another in this order.

Claims

1. A nitride-based semiconductor device, comprising:

a substrate;

a first group III nitride-based semiconductor layer formed on said substrate and including gallium;

at least one set of layered structures formed on said first group III nitride-based semiconductor layer and including a super lattice multi-layer film and a second group III nitride-based semiconductor layer in this order; and

a third group III nitride-based semiconductor layer formed on said at least one set of layered structures and including a device region,

said super lattice multi-layer film including at least one pair of alternately layered first and second films,

said first film being made of a group III nitride-based semiconductor including at least indium and gallium and having a first lattice constant,

said second film being made of a group III nitride-based semiconductor including at least aluminum and gallium and having a second lattice constant different from said first lattice constant.

2. The nitride-based semiconductor device according to

claim 1

, wherein

said at least one set of layered structures comprises multiple sets of layered structures placed on said first group III nitride-based semiconductor layer, and said second group III nitride-based semiconductor layers included in said multiple sets of layered structures have the same composition or different compositions.

3. The nitride-based semiconductor device according to

claim 1

, wherein

the average lattice constant of said first film and said second film in said super lattice multi-layer film is substantially equal to the lattice constant of said first group III nitride-based semiconductor layer.

4. The nitride-based semiconductor device according to

claim 1

, wherein

said second group III nitride-based semiconductor layer includes gallium.

5. The nitride-based semiconductor device according to

claim 1

, wherein

said first group III nitride-based semiconductor layer is made of GaN, said second group III nitride-based semiconductor layer is made of GaN, said first film in said super lattice multi-layer film is made of InGaN, and said second film in said super lattice multi-layer film is made of AlGaN.

6. The nitride-based semiconductor device according to

claim 5

, wherein

in said super lattice multi-layer film, the In composition ratio in said first film is 5%, and the Al composition ratio in said second film is 25%.

7. The nitride-based semiconductor device according to

claim 5

, wherein

said first and second films in said super lattice multi-layer film each have a thickness in the range from 5 Å

to 7 Å

.

8. The nitride-based semiconductor device according to

claim 5

, wherein

said first and second films in said super lattice multi-layer film each have a thickness in the range from 5 Å

to 40 Å

.

9. The nitride-based semiconductor device according to

claim 5

, wherein

said at least one pair of said first and second films is at least two pairs and at most nine pairs.

10. The nitride-based semiconductor device according to

claim 5

, wherein

said at least one pair of said first and second films is at least three pairs and at most six pairs.

11. The nitride-based semiconductor device according to

claim 5

, wherein

said at least one set of layered structures includes three sets of layered structures.

12. A method of manufacturing a nitride-based semiconductor device, comprising the steps of:

forming a first group III nitride-based semiconductor layer including gallium on a substrate;

forming at least one set of layered structures including a super lattice multi-layer film and a second group III nitride-based semiconductor layer in this order on said first group III nitride-based semiconductor layer; and

forming a third group III nitride-based semiconductor layer having a device region on said at least one set of layered structures,

said step of forming said at least one set of layered structures comprising the step of forming said super lattice multi-layer film by forming at least one pair of first and second films alternately layered on one another,

said first film being made of a group III nitride-based semiconductor including at least indium and gallium and having a first lattice constant,

said second film being made of a group III nitride-based semiconductor including at least aluminum and gallium and having a second lattice constant different from said first lattice constant.

13. The method of manufacturing a nitride-based semiconductor device according to

claim 12

, wherein

said step of forming at least one set of layered structures comprises the step of placing multiple sets of layered structures on said first group III nitride-based semiconductor layer, and

said second group III nitride-based semiconductor layers included in said multiple sets of layered structures have the same composition or different compositions.

14. The method of manufacturing a nitride-based semiconductor device according to

claim 12

, wherein

said step of forming said at least one set of layered structures comprises the step of setting the same composition for said first and second films in said super lattice multi-layer film so that the average lattice constant of said first and second films is substantially equal to the lattice constant of said first group III nitride-based semiconductor layer.

15. The method of manufacturing a nitride-based semiconductor device according to

claim 12

, wherein

said step of forming said at least one set of layered structures comprises the step of forming said second group III nitride-based semiconductor layer including gallium.

16. The method of manufacturing a nitride-based semiconductor device according to

claim 12

, wherein

said step of forming said first group III nitride-based semiconductor layer comprises the step of forming said first group III nitride-based semiconductor layer made of GaN, and

said step of forming at least one set of layered structures comprises the step of forming said second group III nitride-based semiconductor layer made of GaN and the step of forming at least one pair of said first film made of InGaN and said second film made of AlGaN to form said super lattice multi-layer film.