AlGaN Nitride Region Structure for Lower Dislocation Density
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Solution Overview
Problem
Current nitride semiconductor devices face challenges in improving characteristics such as dislocation density and crystal quality, which affect their performance and efficiency.
Innovation Solution
The nitride semiconductor structure includes multiple regions with specific AlGaN compositions and carbon concentrations, where the second nitride region with higher carbon concentration is between the first and third regions, and the third region has a lower carbon concentration, allowing for controlled strain and dislocation bending, thereby reducing dislocation density and enhancing crystal quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a nitride semiconductor structure with multiple regions of different Al composition ratios is formed, then dislocation density is reduced and crystal quality is improved, but device complexity and manufacturing process difficulty increase
Solution Approach 1:
The nitride semiconductor is divided into multiple regions (first, second, third, and fourth nitride regions) with different Al composition ratios. Each region serves a specific function in managing dislocations and controlling crystal quality, with the Al composition ratio varying systematically from 0.05-0.20 in the first region to 0.25-0.40 in the fourth region, creating a gradient structure that progressively reduces dislocation density
Solution Approach 2:
Each nitride region is assigned a specific Al composition ratio range tailored to its position and function within the structure. The first region has lower Al content (0.05-0.20) for initial crystal growth, the second region has intermediate content (0.20-0.30) for transition, and the third and fourth regions have higher content (0.30-0.40) for dislocation management, optimizing local crystal quality at each stage
2Reliability
If carbon concentration is increased in the second nitride region, then dislocation bending is enhanced and dislocation density is reduced, but manufacturing precision control becomes more difficult
Solution Approach 1:
The patent systematically varies the carbon concentration parameter across different nitride regions, with the second region containing higher carbon concentration (5×10^18 to 5×10^20 atoms/cm³) compared to other regions. This parameter change induces strain that bends dislocations, redirecting them away from critical areas and reducing overall dislocation density in the active device regions
3Reliability
If multiple nitride regions with varying Al composition ratios are formed, then electron mobility is enhanced, but manufacturing process complexity increases
Solution Approach 1:
The Al composition ratio is dynamically adjusted across different regions rather than maintaining a uniform composition. The gradient structure allows the material properties to transition smoothly from one region to another, optimizing electron mobility in the active regions while managing dislocations in the buffer regions, achieving high performance without requiring abrupt interfaces that would complicate manufacturing
Data Source
AI summary
According to one embodiment, a nitride semiconductor includes a nitride member. The nitride member includes a first nitride region including Alx1Ga1-x1N (0<x1≤1), a second nitride region including Alx2Ga1-x2N (0<x2<1, x2<x1), and a third nitride region. The second nitride region is between the first nitride region and the third nitride region. The third nitride region includes Al, Ga, and N. The third nitride region does not include carbon, alternatively a third carbon concentration in the third nitride region is lower than a second carbon concentration in the second nitride region.