Group III-V semiconductor light emitting devices with reduced piezoelectric fields and increased efficiency

• US 6,569,704 B1
• Filed: 11/21/2000
• Issued: 05/27/2003
• Est. Priority Date: 09/30/1997
• Status: Expired due to Term

• Current Assignee: Lumileds LLC (Apollo Global Management, Inc.)
• Original Assignee: Lumileds Lighting US LLC (Apollo Global Management, Inc.)
• Inventors: Amano, Hiroshi, Takeuchi, Tetsuya, Akasaki, Isamu, Yamada, Norihide
• Primary Examiner(s): JACKSON JR, JEROME
• Application Number:
  US09/717,647
• Time in Patent Office: 917 Days
• Field of Search: 257/14, 257/21, 257/18, 257/103, 257/190, 257/673, 438/94
• US Class Current: 438/94
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: H01L 33/16 with a particular crystal structure or orientation, e.g. polycrystalline, amorphous or porous
• CPC Class Codes: H01L 33/18 within the light emitting region
• CPC Class Codes: H01L 33/24 of the light emitting region, e.g. non-planar junction
• CPC Class Codes: H01L 33/32 containing nitrogen
• CPC Class Codes: H01S 5/0035 Simulations of laser characteristics
• CPC Class Codes: H01S 5/021 Silicon based substrates
• 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 5/3201 incorporating bulkstrain effects, e.g. strain compensation, strain related to polarisation
• CPC Class Codes: H01S 5/32025 non-polar orientation
• CPC Class Codes: H01S 5/320275 semi-polar orientation
• CPC Class Codes: H01S 5/343 in AIIIBV compounds, e.g. AlGaAs-laser , InP-based laser
• CPC Class Codes: H01S 5/34333 with a well layer based on Ga(In)N or Ga(In)P, e.g. blue laser

Abstract

An optical semiconductor device having a plurality of GaN-based semiconductor layers containing a strained quantum well layer in which the strained quantum well layer has a piezoelectric field that depends on the orientation of the strained quantum well layer when the quantum layer is grown. In the present invention, the strained quantum well layer is grown with an orientation at which the piezoelectric field is less than the maximum value of the piezoelectric field strength as a function of the orientation. In devices having GaN-based semiconductor layers with a wurtzite crystal structure, the growth orientation of the strained quantum well layer is tilted at least 1° from the {0001} direction of the wurtzite crystal structure. In devices having GaN-based semiconductor layers with a zincblende crystal structure, the growth orientation of the strained quantum well layer is tilted at least 1° from the {111} direction of the zincblende crystal structure. In the preferred embodiment of the present invention, the growth orientation is chosen to minimize the piezoelectric field in the strained quantum well layer.

Claims

1. A method for fabricating a GaN-based optical semiconductor device, said method comprising:

growing a first semiconductor layer overlying a substrate, said first semiconductor layer being grown with a first facet orientation;

altering a surface of said first semiconductor layer such that said altered surface provides a growth orientation having a second facet orientation for a subsequent semiconductor layer grown thereon, said second facet orientation differing from said first facet orientation; and

growing a strained quantum well layer overlying said altered surface, wherein at least a portion of the strained quantum well layer has said second facet orientation.

2. The method of claim 1 wherein altering said surface of said first semiconductor layer comprises selectively etching said first semiconductor layer.

3. The method of claim 1 further comprising growing a second semiconductor layer overlying said strained quantum well layer, said second semiconductor layer being grown with a facet orientation equal to said first facet orientation.

4. The method of claim 1 wherein altering said surface of said first semiconductor layer comprises selectively growing said first semiconductor layer.

5. The method of claim 1 further comprising selecting said second facet orientation to reduce a magnitude of an electric field strength in said quantum well layer.

6. The method of claim 1 wherein said quantum well layer has a wurtzite crystal structure and said second facet orientation is tilted at least 1°

from the {0001} direction of said wurtzite crystal structure.

7. The method of claim 6 wherein said second facet orientation is tilted at least 10°

from the {0001} direction of said wurtzite crystal structure.

8. The method of claim 6 said second facet orientation is tilted from the {0001} direction of said wurtzite crystal structure at an angle selected from about 30°

to about 50°

, about 80°

to about 100°

, and about 130°

to about 150°

.

9. The method of claim 1 wherein said quantum well layer has a zincblende crystal structure and said second facet orientation is tilted at least 1°

from the {111} direction of said zincblende crystal structure.