Gallium Oxide Layer Structure for Crack-Resistant Interfaces
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Solution Overview
Problem
Gallium oxide-based semiconductor devices face issues with cracks at the interface between n-type and i-type semiconductor layers due to significant differences in lattice constants, leading to stress and potential cracking during manufacturing and usage.
Innovation Solution
A semiconductor device structure with a first n-type gallium oxide-based semiconductor layer and a second n-type layer having a higher electrically active donor concentration, where the difference in donor concentration between the two layers is minimized, reducing the lattice constant difference and stress at the interface, and incorporating a transition layer to further suppress cracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an i-type semiconductor layer with low donor concentration is formed on an n-type semiconductor layer with high donor concentration, then the carrier concentration difference between layers is increased, but the lattice constant difference and stress at the interface increase causing cracks
Solution Approach 1:
The patent changes the donor concentration parameter of the semiconductor layer from low (i-type) to high (n-type with 1×10^18 to 1×10^20 atoms/cm³), which reduces the lattice constant difference and stress at the interface between layers, preventing cracks while maintaining the necessary carrier concentration difference for device operation
Solution Approach 2:
The patent creates a gradient in donor concentration across the semiconductor layer thickness, with the donor concentration being higher near the interface with the n-type layer and decreasing toward the opposite side. This local variation in quality allows the interface region to have matched lattice constants (reducing stress) while the bulk maintains the required carrier concentration difference for device function
2Strength
If the donor concentration difference between semiconductor layers is reduced, then the lattice constant difference and stress are minimized, but the carrier concentration difference needed for device operation may be compromised
Solution Approach 1:
The patent simultaneously optimizes two parameters: the average donor concentration is set to 1×10^18 to 1×10^20 atoms/cm³ (higher than conventional i-type) to reduce lattice mismatch, while the thickness is controlled at 10 nm to 10 μm to maintain the necessary carrier concentration gradient for device operation, achieving both interface strength and device reliability
Solution Approach 2:
The patent introduces the thickness dimension (10 nm to 10 μm) as a critical parameter to resolve the contradiction. By controlling the layer thickness, the patent enables the donor concentration to be high enough to reduce lattice mismatch stress while still maintaining sufficient carrier concentration difference across the layer for proper device operation
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The approach effectively reduces stress at the interface, minimizing the occurrence of cracks and enhancing the reliability of the semiconductor device by maintaining a smaller difference in donor concentration and carrier concentration between the layers.
Implementation Method 1
significant differences in lattice constants, leading to stress and potential cracking during manufacturing and usage
Implementation Method 2
leading to stress and potential cracking during manufacturing and usage
Data Source
AI summary
A semiconductor device includes: a first semiconductor layer having an N conductive type and made of a gallium oxide-based semiconductor; and a second semiconductor layer made of a gallium oxide-based semiconductor, in contact with the first semiconductor layer, and having the N conductive type with an electrically active donor concentration higher than an electrically active donor concentration of the first semiconductor layer. A difference between a donor concentration of the first semiconductor layer and a donor concentration of the second semiconductor layer is smaller than a difference between the electrically active donor concentration of the first semiconductor layer and the electrically active donor concentration of the second semiconductor layer.