Method for manufacturing gallium nitride compound semiconductor and light emitting element

• US 20030094618A1
• Filed: 03/06/2002
• Published: 05/22/2003
• Est. Priority Date: 06/01/2000
• Status: Active Grant

• Current Assignee: Nitride Semiconductors Co., Ltd.
• Original Assignee: Nitride Semiconductors Co., Ltd., Shiro Sakai
• Inventors: Sakai, Shiro
• Granted Patent: US 6,861,270 B2
• Time in Patent Office: Days
• US Class Current: 257/85
• CPC Class Codes: H01L 33/06 within the light emitting region, e.g. quantum confinement structure or tunnel barrier
• CPC Class Codes: H01L 33/08 with a plurality of light emitting regions, e.g. laterally discontinuous light emitting layer or photoluminescent region integrated within the semiconductor body H01L27/15 takes precedence
• CPC Class Codes: H01L 33/32 containing nitrogen

Abstract

A method for manufacturing a GaN compound semiconductor which can improve light emitting efficiency even when dislocations are present. An n type AlGaN layer, a undoped AlGaN layer, and a p type AlGaN layer are laminated on a substrate to obtain a double hetero structure. When the undoped AlGaN layer is formed, droplets of Ga or Al are formed on the n type AlGaN layer. The compositional ratio of Ga and Al in the undoped AlGaN layer varies due to the presence of the droplets, creating a spatial fluctuation in the band gap. Because of the spatial fluctuation in the band gap, the percentage of luminous recombinations of electrons and holes is increased.

Claims

1. A method for manufacturing a gallium nitride compound semiconductor, comprising the steps of:

(a) forming a first gallium nitride compound semiconductor on a substrate;

(b) forming of a composition material of the first gallium nitride compound semiconductor a discrete area on the first gallium nitride compound semiconductor; and

(c) forming a second gallium nitride compound semiconductor on the first gallium nitride compound semiconductor on which the composition material is formed;

wherein

a spatial fluctuation is created in the band gap by variation in the compositional ratio in the second gallium nitride compound semiconductor created by the composition material.

2. A method according to claim 1, wherein

the first gallium nitride compound semiconductor and the second gallium nitride compound semiconductor are AlGaN;

and

the composition material is Ga or Al.

3. A method for manufacturing a gallium nitride compound semiconductor, comprising the steps of:

(a) forming a base layer on a substrate, the base layer constructed by forming a discrete layer for varying the diffusion lengths of composition materials of a gallium nitride compound semiconductor; and

(b) forming the gallium nitride compound semiconductor on the base layer;

wherein

a spatial fluctuation is created in the band gap by creating a variation in the compositional ratio in the gallium nitride compound semiconductor by varying the diffusion lengths of the composition materials.

4. A method according to claim 3, wherein the gallium nitride compound semiconductor is AlGaN and the layer for varying the diffusion lengths of the composition materials is formed from SiN.

5. A method for manufacturing a gallium nitride compound semiconductor comprising the steps of:

(a) forming, on a substrate, a base layer having a lattice mismatch; and

(b) forming the gallium nitride compound semiconductor on the base layer;

wherein

a spatial fluctuation is created in the band gap of the gallium nitride compound semiconductor by the lattice mismatch.

6. A method according to claim 5, wherein the lattice mismatch is formed by discretely forming at least one of AlN, InN, AlInGaN, Si, AlGaN, and MgN.

7. A method according to claim 5, wherein the gallium nitride compound semiconductor has a superlattice structure of AlGaN and GaN.

8. A light emitting element comprising a gallium nitride compound semiconductor, the light emitting element comprising:

a substrate;

a first gallium nitride compound semiconductor layer formed on the substrate;

a composition material of the first gallium nitride compound semiconductor formed as a discrete area on the first gallium nitride compound semiconductor layer; and

a second gallium nitride compound semiconductor layer having a varied compositional ratio and formed on the first gallium nitride compound semiconductor layer onto which the composition material is formed.

9. A light emitting element according to claim 8, wherein

the first gallium nitride compound semiconductor and the second gallium nitride compound semiconductor are AlGaN;

and

the composition is Ga or Al.

10. A light emitting element comprising a gallium nitride compound semiconductor, the light emitting element comprising:

a substrate;

a base layer formed on the substrate and constructed by forming a discrete layer for varying the diffusion lengths of the composition materials of the gallium nitride compound semiconductor; and

gallium nitride compound semiconductor layer having a varied compositional ratio and formed on the base layer.

11. A light emitting element according to claim 10, wherein the layer for changing the diffusion length of the composition materials is SiN and the gallium nitride compound semiconductor is AlGaN.

12. A light emitting element using a gallium nitride compound semiconductor, the light emitting element comprising:

a substrate;

a base layer formed on the substrate and having a lattice mismatch; and

a gallium nitride compound semiconductor layer formed on the base layer and having a spatial fluctuation in the band gap.

13. A light emitting element according to claim 12,. wherein the gallium nitride compound semiconductor layer has a superlattice structure.