GaN HEMT Layer Structure for Surface Polarization Control
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Solution Overview
Problem
Current GaN-based high electron mobility transistor (HEMT) semiconductor structures suffer from surface polarization and current collapse due to the formation of a surface channel, which affects device operation and reliability.
Innovation Solution
A semiconductor structure is designed with a substrate, seed layer, buffer layer, back barrier layer with V-group element polarity, channel layer, and front barrier layer, which forms two potential wells and conductive channels, controlling and confining carriers to improve stability and reliability by preventing surface polarization and current collapse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional GaN-based HEMT structure is used, then the device can operate at high frequency and temperature, but surface polarization occurs leading to current collapse and reduced reliability
Solution Approach 1:
The invention segments the barrier layer into two distinct parts: a front barrier layer adjacent to the channel layer and a back barrier layer adjacent to the buffer layer. This segmentation allows each barrier layer to perform specific functions - the front barrier layer manages surface polarization effects while the back barrier layer controls carrier confinement, thereby resolving the technical contradiction by eliminating surface polarization-induced current collapse while maintaining high-frequency operation capability
Solution Approach 2:
The invention applies different polarity orientations to different parts of the structure - the front barrier layer has one polarity orientation while the back barrier layer has an opposite polarity orientation. This local quality differentiation enables targeted control of electrical properties at different locations within the device, specifically addressing surface polarization at the front interface while maintaining bulk carrier confinement through the back interface
2Productivity
If the device operates in high-frequency environments, then communication performance is improved, but surface channel formation occurs causing current collapse
Solution Approach 1:
By dividing the barrier layer into front and back segments with opposite polarities, the invention enables the front barrier layer to specifically counteract surface polarization effects that cause current collapse during high-frequency operation, while the back barrier layer maintains the necessary carrier confinement for high-frequency performance
Solution Approach 2:
The front barrier layer with its specific polarity orientation creates a preliminary counteracting effect against surface polarization before it can cause current collapse. This preventive mechanism allows the device to maintain stable operation during high-frequency switching without suffering from current collapse
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 structure effectively reduces surface polarization and current collapse, enhances carrier confinement, and improves the breakdown voltage and reliability of the semiconductor device by forming two conductive channels with different polarities and band gaps.
Implementation Method 1
The back barrier layer has a V-group element polarity
Implementation Method 2
forms two potential wells and conductive channels, controlling and confining carriers
Data Source
AI summary
A semiconductor structure and a semiconductor device are provided. The semiconductor includes a substrate, a seed layer on the substrate, a buffer layer on the seed layer, a back barrier layer with a V-group element polarity on the buffer layer, a channel layer on the back barrier layer, and a front barrier layer on the channel layer.