Multi-Region AlGaN Nitride Structure for Dislocation Suppression
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Solution Overview
Problem
Existing nitride semiconductors face challenges in achieving high quality due to defects caused by dislocations, which affect the leakage current and overall performance of semiconductor devices.
Innovation Solution
A nitride semiconductor structure is proposed, comprising a base body and a nitride member with specific regions of varying oxygen concentrations and thicknesses, where the first nitride region with a higher oxygen concentration is thinner than the second nitride region with a lower oxygen concentration, effectively suppressing dislocation propagation and defect formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a nitride semiconductor structure is used, then high electron mobility and saturation drift velocity are achieved, but dislocation defects and leakage current occur
Solution Approach 1:
The nitride semiconductor is divided into multiple distinct regions (first nitride region with Alx1Ga1-x1N and second nitride region with Alx2Ga1-x2N) having different compositional ratios and properties. This segmentation allows each region to address specific issues: the first region suppresses dislocation propagation while the second region maintains high electron mobility, thereby reducing leakage current without sacrificing performance.
Solution Approach 2:
Different regions of the nitride semiconductor are assigned different local properties through varying Al composition ratios (x1 and x2). The first nitride region has higher Al content to suppress dislocations, while the second region has optimized Al content for high electron mobility. This local quality differentiation enables simultaneous suppression of leakage current and maintenance of high-speed performance in different spatial locations.
2Reliability
If oxygen concentration is increased in the first nitride region, then dislocation propagation is suppressed, but the region thickness must be reduced
Solution Approach 1:
The nitride semiconductor is segmented into a first nitride region with high oxygen concentration and thinner profile for dislocation suppression, and a second nitride region with lower oxygen concentration and greater thickness for maintaining electron transport properties. This segmentation allows the system to achieve dislocation suppression without requiring the entire structure to be thin, thereby maintaining overall device performance.
Solution Approach 2:
The first nitride region is given locally high oxygen concentration and reduced thickness specifically where dislocation suppression is most critical (near the interface with the base body), while the second nitride region has different local properties optimized for electron mobility. This localized quality adjustment achieves dislocation suppression without unnecessarily reducing the overall active region thickness.
Data Source
AI summary
According to one embodiment, a nitride semiconductor includes a base body, and a nitride member. The nitride member includes a first nitride region including Alx1Ga1-x1N (0<x1≤1), and a second nitride region including Alx2Ga1-x2N (0≤x2<1, x2<x1). The first nitride region is between the base body and the second nitride region. The first nitride region includes a first portion and a second portion. The second portion is between the first portion and the second nitride region. An oxygen concentration in the first portion is higher than an oxygen concentration in the second portion. The oxygen concentration in the second portion is not more than 1×1018/cm3. A first thickness of the first portion in a first direction from the first to second nitride regions is thinner than a second thickness of the second portion in the first direction.