AlGaN Semiconductor Layer Composition for Stable Breakdown Voltage
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Solution Overview
Problem
Existing semiconductor devices face challenges in maintaining stable operation and high breakdown voltage due to electric field fluctuations and carrier trap formation, which can lead to increased on-resistance and operational instability.
Innovation Solution
The semiconductor device incorporates a third semiconductor layer with varying Al composition ratios between the third semiconductor portion and the second electrode portion, which relaxes the electric field and suppresses carrier traps, thereby stabilizing device characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional semiconductor structure with uniform composition is used, then the manufacturing process is simple, but electric field fluctuations occur and carrier traps form leading to unstable characteristics
Solution Approach 1:
The patent applies local quality by creating a third semiconductor layer with a composition gradient, where the Al composition ratio varies continuously from 0 to 0.3 along the thickness direction. This localized compositional variation relaxes the electric field specifically in the region between the third semiconductor portion and the second electrode portion, suppressing carrier trap formation and stabilizing device characteristics without requiring complete structural redesign
Solution Approach 2:
The patent changes the compositional parameter of the semiconductor layer by forming a third semiconductor layer with varying Al composition ratios (from 0 to 0.3) in the thickness direction. This parameter change modifies the electrical properties of the layer, enabling electric field relaxation and carrier trap suppression while maintaining structural integrity and avoiding impurity diffusion issues
2Reliability
If the Al composition ratio is increased to reduce on-resistance, then electrical conductivity improves, but breakdown voltage decreases
Solution Approach 1:
The patent applies local quality by confining the high Al composition ratio (0.3) to only the region adjacent to the second electrode portion, while the rest of the third semiconductor layer has lower Al composition ratios (0 to 0.15). This localized high-Al region provides the necessary electrical conductivity to reduce on-resistance, while the lower-Al regions maintain the high breakdown voltage capability
Solution Approach 2:
The patent resolves the contradiction by introducing a compositional gradient along the thickness direction (Z-axis), transitioning from uniform composition to graded composition. This dimensional variation in composition allows the structure to exhibit different electrical properties at different depths, achieving both low on-resistance (near the electrode) and high breakdown voltage (in the bulk region) simultaneously
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 enhances operational stability and suppresses fluctuations in characteristics, allowing for high breakdown voltage and reduced on-resistance, while avoiding the destabilization caused by impurity diffusion.
Implementation Method 1
a third semiconductor layer including Al, Ga and N, a composition ratio of Al in the third semiconductor layer varying in a thickness direction of the third semiconductor layer
Implementation Method 2
relaxes the electric field and suppresses carrier traps, thereby stabilizing device characteristics
Data Source
AI summary
According to one embodiment, a semiconductor device includes a first electrode, a second electrode, a third electrode, and a semiconductor member. The second electrode includes a first electrode portion and a second electrode portion. The semiconductor member includes a first semiconductor layer, a second semiconductor layer, and a third semiconductor layer. The first semiconductor layer includes Alx1Ga1-x1N (0≤x1<1). The first semiconductor layer includes first to sixth partial regions. The second semiconductor layer includes Alx2Ga1-x2N (0<x2<1, x1<x2). The second semiconductor layer includes a first semiconductor portion, a second semiconductor portion, and a third semiconductor portion. The third semiconductor layer includes Al, Ga and N. The third semiconductor layer includes a first portion including Aly1Ga1-y1N (0<y1≤1), and a second portion including Aly2Ga1-y2N (0≤y2<1, y2<y1).