GROUP III NITRIDE SEMICONDUCTOR SUBSTRATE

• US 20200132750A1
• Filed: 03/09/2018
• Published: 04/30/2020
• Est. Priority Date: 03/17/2017
• Status: Active Grant

• Current Assignee: Furukawa Company Limited (Furukawa Electric Company Limited)
• Original Assignee: Furukawa Company Limited (Furukawa Electric Company Limited)
• Inventors: GOTO, Hiroki, ISHIHARA, Yujiro
• Granted Patent: US 11,662,374 B2
• Time in Patent Office: Days
• CPC Class Codes: C30B 25/02 Epitaxial-layer growth
• CPC Class Codes: C30B 25/16 Controlling or regulating controlling or regulating in general G05
• CPC Class Codes: C30B 29/403 AIII-nitrides
• CPC Class Codes: C30B 29/406 Gallium nitride
• CPC Class Codes: G01R 31/2656 using non-ionising electromagnetic radiation, e.g. optical radiation

Abstract

According to the present invention, there is provided a group III nitride semiconductor substrate (free-standing substrate 30) that is formed of group III nitride semiconductor crystals. Both exposed first and second main surfaces in a relationship of top and bottom are semipolar planes. A variation coefficient of an emission wavelength of each of the first and second main surfaces, which is calculated by dividing a standard deviation of an emission wavelength by an average value of the emission wavelength, is 0.05% or less in photoluminescence (PL) measurement in which mapping is performed in units of an area of 1 mm² by emitting helium-cadmium (He—Cd) laser, which has a wavelength of 325 nm and an output of 10 mW or more and 40 mW or less, at room temperature. In a case where devices are manufactured over the free-standing substrate 30, variations in quality among the devices are suppressed.

Claims

1. A group III nitride semiconductor substrate that is formed of group III nitride semiconductor crystals, wherein both exposed first and second main surfaces in a relationship of top and bottom are semipolar planes, and a variation coefficient of an emission wavelength of each of the first and second main surfaces is 0.05% or less in photoluminescence (PL) measurement performed under conditions in which mapping is performed in units of an area of 1 mm² by emitting helium-cadmium (He—

Cd) laser, which has a wavelength of 325 nm and an output of 10 mW or more and 40 mW or less, at room temperature.

2. The group III nitride semiconductor substrate according to claim 1,

wherein a variation coefficient of an emission intensity of the second main surface in PL measurement performed under the conditions is 15% or less.

3. The group III nitride semiconductor substrate according to claim 2,

wherein the variation coefficient of the emission intensity of the second main surface is 10% or less.

4. The group III nitride semiconductor substrate according to claim 2,

wherein the second main surface is a semipolar plane on a Ga polarity side.

5. The group III nitride semiconductor substrate according to claim 1,

wherein a variation coefficient of a half width of a PL spectrum of each of the first and second main surfaces in PL measurement performed under the conditions is 3.0% or less.

6. The group III nitride semiconductor substrate according to claim 1,

wherein a film thickness is 300 μ

m or more and 1000 μ

m or less.