AlGaN Stacked Nitride Structure for Lower Dislocation Density
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Solution Overview
Problem
Existing nitride structures in semiconductor devices face challenges in achieving improved characteristics, such as reduced dislocation density and enhanced insulation properties, due to limitations in current stacked structures.
Innovation Solution
A nitride structure is proposed, comprising a base, a nitride member with Ga and N, and a stacked structure between the base and the nitride member. This stacked structure includes alternating high and low composition films of Alx1Ga1-x1N and Alx2Ga1-x2N, respectively, with specific thickness and orientation configurations to reduce dislocation density and improve insulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional stacked structure is used in nitride semiconductor devices, then the device can be manufactured with standard processes, but the dislocation density remains high and insulation properties are insufficient
Solution Approach 1:
The patent divides the stacked structure into multiple alternating layers of high composition ratio films (Alx1Ga1-x1N with x1≥0.6) and low composition ratio films (Alx2Ga1-x2N with x2<0.6). This segmentation creates a periodic structure that blocks dislocation propagation while maintaining manufacturability through standard semiconductor fabrication processes.
Solution Approach 2:
The patent applies different composition ratios locally within the stacked structure - high Al content in barrier films for dislocation blocking and low Al content in buffer films for stress management. This local quality variation optimizes both dislocation density reduction and insulation properties in different regions of the structure.
2Reliability
If the thickness of high composition films is increased to improve insulation, then insulation properties are enhanced, but dislocation propagation is not effectively blocked
Solution Approach 1:
The patent employs a periodic stacked structure where thin high composition films (3-20 nm) alternating with low composition films create regular barriers to dislocation propagation. This periodic arrangement blocks dislocations at each interface while the cumulative thickness provides sufficient insulation, solving both problems simultaneously.
3Manufacturing precision
If a simple single-layer structure is used, then the manufacturing process is simple, but the crystalline quality and insulation characteristics are insufficient
Solution Approach 1:
The patent creates a composite material structure by stacking films with different Al composition ratios. This composite approach combines the advantages of high-Al films (dislocation blocking) and low-Al films (stress relief) to achieve superior crystalline quality that cannot be obtained with single-layer structures.
4Manufacturing precision
If alternating high and low composition films are stacked to reduce dislocation density, then dislocation propagation is blocked, but the structure becomes more complex
Solution Approach 1:
The patent controls the composition ratio parameter (Al content) to create two distinct film types that alternate in the stack. By precisely controlling this parameter during deposition, the structure achieves complex functionality with a relatively simple binary alternation pattern that is compatible with standard manufacturing.
Data Source
AI summary
According to one embodiment, a nitride structure includes a base, a nitride member including Ga and N, and a stacked structure provided between the base and the nitride member in a first direction. The stacked structure includes a plurality of high composition films including Alx1Ga1-x1N (0<x1≤1), and a plurality of low composition films including Alx2Ga1-x2N (0≤x2<1, x2<x1). A high composition film thickness of one high composition film is thinner than a nitride member thickness of the nitride member in the first direction. A low composition film thickness of one of the plurality of low composition films in the first direction is thinner than the nitride member thickness. The high composition film and the low composition film are provided alternately along the first direction. The plurality of high composition films includes a first film and another film.