Aluminum Oxide Interface Layer for GaN Semiconductor Reliability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The formation of an aluminum oxide layer over a Ga-containing nitride semiconductor layer generates numerous interface states, deteriorating the characteristics of semiconductor devices due to the mismatch in coordination of Al atoms at the interface.
Innovation Solution
A tetra-coordinated and hexa-coordinated Al atom structure in the aluminum oxide layer, with tetra-coordinated Al atoms present by 30% or more in the interface region within 1.5 nm of the nitride semiconductor layer, is formed using an interface layer treated in an oxidizing agent-free atmosphere, improving the interface bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an aluminum oxide layer is formed directly over a Ga-containing nitride semiconductor layer, then the gate insulating film can be formed, but numerous interface states are generated at the interface due to mismatch in Al atom coordination
Solution Approach 1:
The patent introduces an interface layer between the nitride semiconductor layer and the aluminum oxide layer. This interface layer acts as a mediator that gradually transitions the coordination environment from hexa-coordinated Al atoms in the bulk aluminum oxide to tetra-coordinated Al atoms at the interface, reducing the abrupt mismatch and suppressing interface state generation
Solution Approach 2:
The patent creates a specific local structure at the interface region where tetra-coordinated Al atoms are present by 30 atom% or more and less than 50 atom% within 1.5 nm from the interface. This local modification of Al atom coordination improves interface bonding quality without changing the overall structure of the aluminum oxide layer
2Manufacturing precision
If tetra-coordinated Al atoms are increased in the interface region to improve interface bonding, then interface state generation is suppressed, but the manufacturing process becomes more complex requiring heat treatment in oxidizing agent-free atmosphere
Solution Approach 1:
The patent performs heat treatment in an oxidizing agent-free atmosphere before forming the main aluminum oxide layer. This preliminary action creates the interface layer with the desired tetra-coordinated Al atom structure in advance, which then serves as the foundation for subsequent aluminum oxide deposition, simplifying the overall process by establishing the correct interface structure early
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 configuration suppresses the generation of interface states and enhances the BTI characteristics and threshold voltage stability of the semiconductor device.
Implementation Method 1
The interface layer is heat treated in an atmosphere not containing an oxidizing agent
Data Source
AI summary
A first nitride semiconductor layer contains Ga. The first nitride semiconductor layer is, for example, a GaN layer, an AlGaN layer, or an AlInGaN layer. Then, an aluminum oxide layer has tetra-coordinated Al atoms each surrounded by four O atoms and hexa-coordinated Al atoms each surrounded by six O atoms as Al atoms in the interface region with respect to the first nitride semiconductor layer. The interface region is a region apart, for example, by 1.5 nm or less from the interface with respect to the first nitride semiconductor layer. Then, in the interface region, the tetra-coordinated Al atoms are present by 30 at % or more and less than 50 at % based on the total number of Al atoms.