Group III Nitride Substrate Surface Stabilization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The quality of epitaxially grown layers on nitride substrates is degraded due to surface oxidation, leading to poor device performance, necessitating a stable nitride substrate with high crystal quality for effective epitaxial growth.
Innovation Solution
A group III nitride substrate with a surface layer containing 3-25 at.% carbon and 5×10^10 to 200×10^10 atoms/cm^2 of a p-type metal element, along with an insulating metal element, is developed, using dry etching with a mixed gas and polishing with a p-type metal oxide solution to achieve a stable surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the nitride substrate surface is left untreated or conventionally treated, then the substrate can be manufactured with standard processes, but the surface oxidizes and degrades epitaxial layer quality
Solution Approach 1:
The patent applies preliminary action by forming a protective carbon-containing surface layer on the nitride substrate before epitaxial growth. This surface layer is created through surface treatment with carbon sources (such as hydrocarbon gases or carbon-containing liquids) that deposit carbon atoms on the substrate surface, preventing oxidation during subsequent processing and epitaxial growth. The carbon layer acts as a protective barrier that maintains surface stability while enabling high-quality epitaxial layer formation.
Solution Approach 2:
The patent uses carbon as an intermediary substance between the nitride substrate and the oxidizing environment. The carbon-containing surface layer serves as a mediator that protects the underlying nitride substrate from oxidation without interfering with the epitaxial growth process. This intermediary layer allows the substrate to maintain surface stability while enabling the formation of high-quality epitaxial layers.
2Reliability
If the surface is treated to prevent oxidation, then surface stability improves, but the manufacturing process becomes more complex
Solution Approach 1:
The patent applies parameter changes by controlling the carbon concentration and composition in the surface layer to achieve optimal protection. By adjusting parameters such as carbon source type, deposition temperature, treatment time, and carbon partial pressure, the process achieves effective oxidation prevention with manageable complexity. The surface layer is designed to contain carbon within specific concentration ranges that provide protection while maintaining compatibility with subsequent epitaxial growth.
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 approach results in a stable surface III nitride substrate, enabling high-quality epitaxial growth and improved semiconductor device performance with reduced leakage current and enhanced light output.
Implementation Method 1
The quality of an epitaxially grown layer that is formed on the surface of a nitride substrate is degraded if the surface is oxidized
Implementation Method 2
dry etching with a mixed gas
Implementation Method 3
polishing with a p-type metal oxide solution
Implementation Method 4
epitaxial layers are grown while being matched to the lattice of the substrate surface
Data Source
AI summary
A group III nitride substrate in one embodiment has a surface layer. The surface layer contains 3 at. % to 25 at. % of carbon and 5×1010 atoms/cm2 to 200×1010 atoms/cm2 of a p-type metal element. The group III nitride substrate has a stable surface.