Nitride Semiconductor Device Al Composition Control
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Solution Overview
Problem
Current semiconductor devices using nitride semiconductors face challenges in maintaining high carrier mobility and stable threshold voltage due to excessive carrier formation at the bottom of the recess, leading to short channel effects and decreased threshold voltage.
Innovation Solution
The semiconductor device incorporates a nitride member with regions of varying Al composition, where the first nitride region at the bottom of the recess has a lower Al composition than the second nitride region on the side, suppressing excessive carrier formation and maintaining high channel mobility and stable threshold voltage through controlled Al and Ga distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a nitride semiconductor device uses a recess structure, then short channel effects are suppressed, but excessive carrier formation occurs at the bottom of the recess leading to decreased threshold voltage
Solution Approach 1:
The patent applies local quality by creating different Al composition regions within the nitride semiconductor layer. The Al composition is varied spatially: higher Al content at the bottom of the recess to suppress carrier formation, and lower Al content on the sides to maintain channel mobility. This localized compositional variation resolves the contradiction between suppressing excessive carriers and maintaining device performance.
Solution Approach 2:
The patent changes the compositional parameter (Al content) of the nitride semiconductor layer to control carrier formation. By adjusting the Al composition ratio x in AlxGa1-xN from 0 to 0.3, the patent optimizes the balance between suppressing excessive carriers at the recess bottom and maintaining high channel mobility in the active region.
2Reliability
If Al composition is increased to suppress carrier formation, then threshold voltage stability improves, but channel mobility decreases
Solution Approach 1:
The patent resolves this contradiction by applying different Al compositions to different spatial locations. The bottom region (first nitride region) has higher Al content (0.1 ≤ x < 0.3) to suppress carriers, while the side region (second nitride region) has lower Al content (0 ≤ x1 < x2 ≤ 0.3) to maintain mobility. This local differentiation allows both requirements to be satisfied simultaneously.
Solution Approach 2:
The nitride semiconductor layer is segmented into distinct regions with different Al compositions. The first nitride region at the bottom and second nitride region on the sides are clearly separated, each optimized for its specific function: carrier suppression versus mobility maintenance.
Data Source
AI summary
According to one embodiment, a semiconductor device includes first to third electrodes, first and second semiconductor regions, a first insulating member, and a nitride member. The third electrode includes a first electrode portion. A position of the first electrode portion is between a position of the first electrode and a position of the second electrode. The first semiconductor region includes first to fifth partial regions. A position of the fourth partial region is between positions of the first and third partial regions. A position of the fifth partial region is between positions of the third and second partial regions. The second semiconductor region includes first and second semiconductor portions. The first electrode portion is located between the first and second semiconductor portions. The first insulating member includes first to third insulating regions. The nitride member includes first to third nitride regions.