Nitride Semiconductor Gate Leakage Suppression
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Solution Overview
Problem
Semiconductor devices with nitride semiconductors face challenges in achieving stable characteristics due to issues with gate leakage and current collapse, particularly related to carrier concentration and Al composition ratios in the semiconductor layers.
Innovation Solution
A semiconductor device design with a recessed gate structure, featuring Alx1Ga1-x1N and Alx2Ga1-x2N semiconductor layers, and insulating regions, where the thickness and composition of these layers are optimized to control carrier concentration and reduce gate leakage and current collapse, with specific thickness differences and Al composition ratios in the semiconductor parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a nitride semiconductor device with gate electrode structure is used, then high power and high frequency performance is achieved, but gate leakage and current collapse occur leading to unstable characteristics
Solution Approach 1:
The semiconductor device is divided into multiple functional regions: a first region with high carrier concentration for power handling, and a second region with low carrier concentration for reducing gate leakage and preventing current collapse. This spatial segmentation allows simultaneous optimization of power performance and stability.
Solution Approach 2:
Different regions of the semiconductor device are assigned different local properties: the first region has high Al composition ratio and high carrier concentration for power performance, while the second region has low Al composition ratio and low carrier concentration for stability. This local quality differentiation resolves the contradiction between power and stability.
2Stress or pressure
If Al composition ratio in semiconductor layer is increased to improve breakdown voltage, then voltage resistance is improved, but carrier concentration increases leading to higher gate leakage
Solution Approach 1:
The semiconductor layer is segmented into a first region with high Al composition ratio for breakdown voltage and a second region with low Al composition ratio for low gate leakage. This segmentation allows each region to optimize for its specific function without compromising the other.
Solution Approach 2:
Different Al composition ratios are assigned to different regions: high Al ratio in the first region for voltage resistance, low Al ratio in the second region for low gate leakage. This local quality approach simultaneously achieves high breakdown voltage and low gate leakage.
3Power
If carrier concentration is increased to reduce on-resistance, then conductivity is improved, but current collapse occurs under voltage stress
Solution Approach 1:
The device structure is segmented into a first region with high carrier concentration for low on-resistance and a second region with low carrier concentration for current collapse prevention. This segmentation enables both high conductivity and voltage stress resistance.
Solution Approach 2:
Different carrier concentrations are implemented in different regions: high carrier concentration in the first region for conductivity, low carrier concentration in the second region for preventing current collapse under voltage stress.
Data Source
AI summary
According to one embodiment, a semiconductor device includes first to third electrodes, first and second semiconductor layers, and an insulating member. The third electrode in a first direction is between the first and second electrodes in the first direction. The first direction is from the first toward second electrode. The first semiconductor layer includes Alx1Ga1-x1N (0≤x1<1), and first to sixth partial regions. A second direction from the first partial region toward the first electrode crosses the first direction. The second semiconductor layer includes Alx2Ga1-x2N (0<x2<1 and x1<x2), and first and second semiconductor regions. A direction from the fourth partial region toward the first semiconductor region is along the second direction. A direction toward the second semiconductor region from the fifth and sixth partial regions is along the second direction. The insulating member includes first to third insulating regions.