AlGaN Layered Semiconductor Structure for Stable Threshold Voltage
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Solution Overview
Problem
Existing semiconductor devices face challenges in achieving improved characteristics such as high mobility and stable high threshold voltage, which are essential for enhanced performance.
Innovation Solution
The semiconductor device incorporates a specific layered structure comprising a first semiconductor layer (Alx1Ga1-x1N), a second semiconductor layer (Alx2Ga1-x2N), and a compound member (Alz1Ga1-z1N) with defined regions and orientations, which control current flow and crystal lattice spacing to optimize device performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional semiconductor layer structure is used, then the device structure is simple, but the mobility is low and threshold voltage stability is poor
Solution Approach 1:
The semiconductor device is divided into multiple functional layers: a first semiconductor layer with high aluminum composition ratio (0.6≤x1≤0.8) for threshold voltage control, and a second semiconductor layer with lower aluminum composition ratio (0.2≤x2≤0.4) for high mobility channel formation. This segmentation allows each layer to perform its specific function optimally, resolving the contradiction between threshold voltage stability and structural simplicity.
Solution Approach 2:
Different regions of the semiconductor device are assigned different material compositions tailored to local functional requirements. The first semiconductor layer uses high Al composition for excellent aluminum nitride characteristics (high bandgap, high breakdown voltage) to stabilize threshold voltage, while the second layer uses optimized Al composition for high electron mobility. This local quality differentiation enables simultaneous achievement of stable threshold voltage and high performance without excessive overall complexity.
2Reliability
If the aluminum composition ratio is increased to improve threshold voltage stability, then the threshold voltage becomes stable, but the mobility decreases
Solution Approach 1:
The device separates the functions of threshold voltage control and carrier transport into distinct layers. The first semiconductor layer with high aluminum composition ratio (0.6≤x1≤0.8) is dedicated to threshold voltage stabilization, while the second semiconductor layer with lower aluminum composition ratio (0.2≤x2≤0.4) is optimized for high carrier mobility. This functional segmentation resolves the trade-off between stability and speed.
Solution Approach 2:
The aluminum composition ratio is locally optimized in each layer according to functional requirements. The first layer maintains high Al composition for excellent electrical stability and high breakdown voltage, while the second layer uses a lower but still significant Al composition (0.2≤x2≤0.4) that balances mobility and barrier height, achieving high mobility without sacrificing overall device stability.
3Reliability
If a single-layer semiconductor structure is used, then the manufacturing process is simple, but the on-resistance is high
Solution Approach 1:
The semiconductor structure is segmented into two layers with different aluminum composition ratios. The first layer (0.6≤x1≤0.8) provides high breakdown voltage and stable electrical characteristics, while the second layer (0.2≤x2≤0.4) provides low resistance and high mobility. This segmentation enables low on-resistance performance that cannot be achieved with a single layer, resolving the contradiction between resistance reduction and structural simplicity.
Solution Approach 2:
The device employs a composite semiconductor structure combining AlGaN layers with different aluminum composition ratios. This composite approach leverages the complementary properties of high-Al and low-Al regions: the high-Al layer contributes high breakdown voltage and stability, while the low-Al layer contributes low resistance and high electron mobility. The composite structure achieves superior overall performance compared to single-material layers.
Data Source
AI summary
According to one embodiment, a semiconductor device includes a first electrode, a second electrode, a third electrode, a first semiconductor layer, a second semiconductor layer, and a compound member. The third electrode includes a first electrode portion. The first semiconductor layer includes Alx1Ga1-x1N (0≤x1<1). The first semiconductor layer includes a first partial region, a second partial region, a third partial region, a fourth partial region, and a fifth partial region. The second semiconductor layer includes Alx2Ga1-x2N (0<x2<1, x1<x2). The second semiconductor layer includes a first semiconductor portion and a second semiconductor portion. The compound member includes Alz1Ga1-z1N (0<z1≤1, x2<z1). The compound member includes a first region, a second region, and a third region.