AlGaN Semiconductor Device Threshold Voltage Control
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Solution Overview
Problem
Semiconductor devices using nitride semiconductors face challenges in achieving easy operation and control over threshold voltage, particularly in ensuring normally-off operation and high degrees of freedom in threshold voltage adjustment.
Innovation Solution
The semiconductor device incorporates a first semiconductor layer of Alx1Ga1-x1N with a polycrystalline nitride electrode, a second semiconductor layer with Alx2Ga1-x2N regions, and an insulating layer, where the electrode is positioned in a specific direction relative to the semiconductor layer, enabling control over the threshold voltage through doping concentration and using materials like AlN or BN for the gate electrode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a nitride semiconductor device is designed to achieve normally-off operation with high threshold voltage control, then operational safety and ease of use are improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The device is divided into distinct functional regions: a first semiconductor layer for channel formation, a second semiconductor layer with AlGaN regions for threshold voltage control, and an insulating layer for electrical isolation. This segmentation allows independent optimization of each region to achieve normally-off operation while maintaining manageable device complexity.
Solution Approach 2:
The patent applies local quality by creating AlGaN regions with specific aluminum compositions (x2) in the second semiconductor layer, positioned at particular locations to control threshold voltage. The doping concentration is also locally varied to achieve the desired electrical characteristics for normally-off operation without requiring complex global device redesign.
2Adaptability or versatility
If threshold voltage control freedom is increased through doping concentration adjustment, then adaptability is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent utilizes parameter changes by adjusting the doping concentration in the AlGaN regions of the second semiconductor layer to control threshold voltage. By varying this parameter within a specific range, the device achieves high degrees of freedom in threshold voltage adjustment while maintaining manufacturability through standard doping processes.
Solution Approach 2:
The device employs composite material structures combining AlGaN regions with different aluminum compositions (x2) in the second semiconductor layer, integrated with the first semiconductor layer and insulating layer. This composite structure provides multiple degrees of freedom for threshold voltage control through material composition and doping variations, achieving adaptability without excessive manufacturing precision requirements.
Data Source
AI summary
According to one embodiment, a semiconductor device includes a first element portion. The first element portion includes first and second semiconductor layers, first, second and third electrodes, and a first insulating layer. The first semiconductor layer includes Alx1Ga1-x1N (0≤x1<1). The first electrode is separated from the first semiconductor layer. The first electrode includes a polycrystal of a nitride of one of Al or B. The second semiconductor layer includes Alx2Ga1-x2N (x1<x2<1). The second semiconductor layer includes first to third regions. The first region is positioned between the second and third regions. The first region is provided between the first semiconductor layer and the first electrode. The first insulating layer is provided between the first region and the first electrode. The second electrode is electrically connected to the second region. The third electrode is electrically connected to the third region.