GaN Substrate Storage Inert Atmosphere Oxidation Prevention
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Solution Overview
Problem
Conventional methods for storing GaN substrates lead to oxidation due to clean air atmospheres, resulting in unfavorable properties for semiconductor devices.
Innovation Solution
Storing GaN substrates in an atmosphere with an oxygen concentration of 18 vol. % or less and a water-vapor concentration of 25 g/m3 or less, using techniques such as gas control and scavengers to maintain low oxygen and water vapor levels, and controlling surface roughness and off-axis angles to prevent oxidation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If GaN substrates are stored under clean air atmosphere, then storage is simple and convenient, but the surface of the GaN substrates oxidizes due to prolonged storage
Solution Approach 1:
The patent applies inert atmosphere storage by replacing clean air with an atmosphere having controlled oxygen concentration (18 vol.% or less) and water-vapor concentration (25 g/m³ or less). This inert environment prevents oxidation of the GaN substrate surface while maintaining storage simplicity, directly resolving the contradiction between storage convenience and prevention of surface oxidation.
2Duration of action of stationary object
If GaN substrates are stored for prolonged periods, then manufacturing flexibility is improved, but surface oxidation occurs making device manufacturing unfavorable
Solution Approach 1:
By maintaining an inert atmosphere with controlled oxygen (18 vol.% or less) and water-vapor (25 g/m³ or less) concentrations throughout the storage period, the patent enables prolonged storage without surface oxidation. This ensures that even after extended storage, the GaN substrates maintain favorable properties for semiconductor device manufacturing, resolving the contradiction between storage duration and device reliability.
Solution Approach 2:
The patent applies parameter changes by precisely controlling the atmospheric composition parameters - oxygen concentration at 18 vol.% or less and water-vapor concentration at 25 g/m³ or less. These parameter controls prevent oxidation reactions during prolonged storage, allowing extended storage periods while maintaining substrate quality suitable for high-performance semiconductor device manufacturing.
3Object-affected harmful factors
If oxygen concentration is reduced to prevent oxidation, then surface quality is improved, but storage atmosphere control complexity increases
Solution Approach 1:
The patent implements inert atmosphere storage with oxygen concentration of 18 vol.% or less and water-vapor concentration of 25 g/m³ or less. This approach prevents surface oxidation of GaN substrates while using relatively simple control methods such as sealed containers with desiccants or controlled gas environments, achieving oxidation prevention without excessive system complexity.
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
This method prevents oxidation of GaN substrates, enabling the manufacture of semiconductor devices with improved properties by maintaining low oxygen and water vapor concentrations and optimizing surface conditions.
Implementation Method 1
the surface of the GaN substrates oxidizes due to the prolonged storage... an atmosphere having an oxygen concentration of 18 vol. % or less, and/or a water-vapor concentration of 25 g/m3 or less
Data Source
AI summary
Affords a method of storing GaN substrates from which semiconductor devices of favorable properties can be manufactured, the stored substrates, and semiconductor devices and methods of manufacturing the semiconductor devices. In the GaN substrate storing method, a GaN substrate (1) is stored in an atmosphere having an oxygen concentration of 18 vol. % or less, and/or a water-vapor concentration of 12 g/m3 or less. Surface roughness Ra of a first principal face on, and roughness Ra of a second principal face on, the GaN substrate stored by the storing method are brought to no more than 20 nm and to no more than 20 μm, respectively. In addition, the GaN substrates are rendered such that the principal faces form an off-axis angle with the (0001) plane of from 0.05° to 2° in the <1 100> direction, and from 0° to 1° in the <11 20> direction.