Buffer Layer Dislocation Control for Semiconductor Reliability
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Solution Overview
Problem
Conventional semiconductor devices with nitride-based compound semiconductors face challenges in achieving high buffer layer resistance without deteriorating current collapse and increasing threshold voltage, leading to leak current issues and reduced controllability.
Innovation Solution
The semiconductor device incorporates a buffer layer with specific dislocation density, X-ray rocking curve half-width, and screw dislocation density ratios to maximize volume resistivity, ensuring high resistance and breakdown voltage without increasing threshold voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If impurity doping is used to increase buffer layer resistance, then resistance value increases, but current collapse occurs
Solution Approach 1:
The invention changes the physical and chemical parameters of the buffer layer by controlling dislocation density within a specific range (1×10^8 to 1×10^10 cm^-2) and adjusting the composition ratio of AlxGa1-xN (0 < x < 0.5). This parameter optimization achieves high resistance (10^5 Ω·cm or higher) without causing current collapse, resolving the contradiction between reliability improvement and harmful effect prevention.
Solution Approach 2:
The invention uses composite material structure with AlxGa1-xN alloy buffer layer containing controlled dislocations, combining the benefits of high resistance with maintained electrical stability. The composite nature of the buffer layer (alloy composition + dislocation control) prevents current collapse while achieving the desired resistance level.
2Reliability
If breakdown voltage is increased, then voltage resistance improves, but threshold voltage increases reducing controllability
Solution Approach 1:
The invention optimizes the composition ratio parameter x in AlxGa1-xN within the range 0 < x < 0.5 to achieve a balance between breakdown voltage and threshold voltage. By precisely controlling this composition parameter and dislocation density, the device attains high breakdown voltage while maintaining acceptable threshold voltage for controllability.
Data Source
AI summary
A semiconductor device includes a substrate; a buffer layer; and a compound semiconductor layer laminated on the substrate with the buffer layer in between. The buffer layer has a dislocation density in a plane in parallel to an in-plane direction thereof, so that a volume resistivity of the buffer layer becomes a substantially maximum value.