Group III Nitride Semiconductor Polarity Inversion via Laser Irradiation
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Solution Overview
Problem
Group III nitride semiconductors grown on sapphire substrates exhibit polarity differences between surfaces, leading to disparities in surface characteristics such as flatness, crystallinity, and etching behavior, necessitating a method to achieve identical polarity on opposing surfaces.
Innovation Solution
A surface treatment method involving laser irradiation of a nitrogen-polarized surface to change its polarity to match a gallium-polarized surface, with optional formation of a crystal damage layer through plasma treatment or ion beam irradiation to create defects and facilitate polarity inversion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a group III nitride semiconductor is grown on a sapphire substrate, then the semiconductor can be manufactured using a cost-effective substrate, but the opposing surfaces exhibit different polarities leading to inferior surface characteristics on the nitrogen polarity surface
Solution Approach 1:
The patent applies polarity inversion by irradiating the nitrogen polarity surface with a laser beam to transform it into a group III polarity surface. This inversion technique converts the inherently inferior nitrogen polarity surface into a surface with superior characteristics matching the group III polarity surface, thereby resolving the contradiction between using cost-effective sapphire substrates and achieving high surface flatness.
2Ease of manufacture
If a group III nitride semiconductor is grown on a sapphire substrate, then the semiconductor can be manufactured using a cost-effective substrate, but the opposing surfaces exhibit different polarities leading to inferior crystallinity on the nitrogen polarity surface
Solution Approach 1:
The patent applies polarity inversion by irradiating the nitrogen polarity surface with a laser beam to transform it into a group III polarity surface. This inversion technique converts the inherently inferior nitrogen polarity surface into a surface with superior characteristics matching the group III polarity surface, thereby resolving the contradiction between using cost-effective sapphire substrates and achieving high surface flatness.
3Ease of manufacture
If a group III nitride semiconductor is grown on a sapphire substrate, then the semiconductor can be manufactured using a cost-effective substrate, but the opposing surfaces exhibit different polarities leading to inferior electrical characteristics on the nitrogen polarity surface
Solution Approach 1:
The patent applies polarity inversion by irradiating the nitrogen polarity surface with a laser beam to transform it into a group III polarity surface. This inversion technique converts the inherently inferior nitrogen polarity surface into a surface with superior characteristics matching the group III polarity surface, thereby resolving the contradiction between using cost-effective sapphire substrates and achieving high surface flatness.
4Ease of manufacture
If a group III nitride semiconductor is grown on a sapphire substrate, then the semiconductor can be manufactured using a cost-effective substrate, but the opposing surfaces exhibit different polarities leading to poor light emitting efficiency
Solution Approach 1:
The patent applies polarity inversion by irradiating the nitrogen polarity surface with a laser beam to transform it into a group III polarity surface. This inversion technique converts the inherently inferior nitrogen polarity surface into a surface with superior characteristics matching the group III polarity surface, thereby resolving the contradiction between using cost-effective sapphire substrates and achieving high surface flatness.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method ensures identical group III polarity on both surfaces, improving surface flatness, crystallinity, and electrical properties, and enhancing light emitting efficiency in semiconductor devices.
Implementation Method 1
irradiating a laser beam onto the second surface to change the nitrogen polarity of the second surface to the group III polarity
Implementation Method 2
forming a crystal damage layer having a defect caused by nitrogen vacancies along the second surface, before the irradiating a laser beam onto the second surface. The forming a crystal damage layer may include performing plasma treatment or ion beam irradiation on the second surface.
Implementation Method 3
forming a crystal damage layer having a defect caused by nitrogen vacancies along the second surface, before the irradiating a laser beam onto the second surface. The forming a crystal damage layer may include performing plasma treatment or ion beam irradiation on the second surface.
Data Source
AI summary
There is provided a surface treatment method of a group III nitride semiconductor including: providing a group III nitride semiconductor including a first surface having a group III polarity and a second surface opposing the first surface and having a nitrogen polarity; and irradiating a laser beam onto the second surface to change the nitrogen polarity of the second surface to the group III polarity.