Nitride semiconductor crystal with surface texture

• US 8,158,993 B2
• Filed: 08/23/2007
• Issued: 04/17/2012
• Est. Priority Date: 08/28/2006
• Status: Expired due to Fees

• Current Assignee: Stanley Electric Company Limited
• Original Assignee: Stanley Electric Company Limited
• Inventors: Liang, Ji-Hao, Tsuchiya, Masahiko, Chinone, Takako, Kajikawa, Masataka
• Primary Examiner(s): Matthews, Colleen
• Assistant Examiner(s): YUSHINA, GALINA G
• Application Number:
  US11/843,916
• Publication Number:
  US 20080073657A1
• Time in Patent Office: 1,699 Days
• Field of Search: 257/94, 257/98, 257/103, 257/E33.001, 257/E33.025, 257/E33.029, 257/79, 257/95, 257/521, 257/627, 257/89
• US Class Current: 257/89
• CPC Class Codes: H01L 33/0075 comprising nitride compounds
• 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 33/24 of the light emitting region, e.g. non-planar junction
• CPC Class Codes: H01L 33/32 containing nitrogen

Abstract

A nitride semiconductor light emitting device is formed by: forming a resist pattern on a first nitride semiconductor layer formed on a substrate, the resist pattern having a region whose inclination angle relative to a substrate surface changes smoothly as viewed in a cross section perpendicular to the substrate surface; etching the substrate by using the resist pattern as a mask to transfer the resist pattern to the first nitride semiconductor layer; and forming an light emitting layer on the patterned first nitride semiconductor layer. The nitride semiconductor light emitting device can emit near-white light or have a wavelength range generally equivalent to or near visible light range.

Claims

1. A nitride semiconductor light emitting device comprising:

a substrate;

a semiconductor layer formed on the substrate and having a plurality of projections, wherein an inclination angle of a surface of each projection relative to a substrate surface changes smoothly as viewed in a cross section perpendicular to the substrate surface, wherein the inclination angle of the surface of each projection changes smoothly within 0 to 30 degrees; and

a quantum well formed on the semiconductor layer and comprising material containing GaN, wherein an inclination angle of a surface of the quantum well changes smoothly within 0 to 3 degrees along an a-axis direction and within 0 to 30 degrees along an m-axis direction.

2. The nitride semiconductor device according to claim 1, wherein the plurality of projections are disposed in a hexagonal close-packed configuration.

3. The nitride semiconductor device according to claim 1, wherein the plurality of projections comprise a plurality of types of projections having different heights.

4. The nitride semiconductor light emitting device according to claim 1, wherein the quantum well comprises a composition adjusted to obtain optical emission in a range of 420 to 600 nm.

5. A nitride semiconductor crystal comprising:

a substrate;

a semiconductor layer formed on the substrate and having a plurality of projections, a surface of each projection including a region whose inclination angle relative to a substrate surface changes smoothly as viewed in a cross section perpendicular to the substrate surface, wherein the inclination angle of the surface of each projection changes smoothly within 0 to 30 degrees; and

a quantum well formed on the semiconductor layer and comprising a material containing GaN, wherein an inclination angle of a surface of the quantum well changes smoothly within 0 to 3 degrees along an a-axis direction and within 0 to 30 degrees along the m-axis direction.