Gallium Oxide N-Type Layer Structure for Low-Stress 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 with a higher electrically active donor concentration, where the difference in donor concentration between the two layers is minimized, reducing lattice constant differences and stress at the interface, and incorporating a transition layer to further suppress cracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an n-type semiconductor layer and an i-type semiconductor layer are formed with significantly different donor concentrations, then the electrically active donor concentration difference is improved, but the lattice constant difference increases causing stress and cracks at the interface
Solution Approach 1:
The patent applies parameter changes by carefully controlling the donor concentration in the semiconductor layers. Specifically, it maintains the donor concentration difference (for electrical performance) while minimizing the lattice constant difference (for mechanical stability) through precise compositional control of the gallium oxide-based semiconductor layers.
Solution Approach 2:
The patent uses composite materials by creating a multi-layer structure with different gallium oxide-based semiconductor compositions. The first and second n-type layers have different donor concentrations but are both made of gallium oxide-based semiconductor, allowing electrical differentiation while maintaining material compatibility to reduce interface stress and cracking.
2Stress or pressure
If the donor concentration difference between layers is minimized, then lattice constant difference and stress are reduced, but the electrically active donor concentration difference needed for device function is compromised
Solution Approach 1:
The patent simultaneously optimizes multiple parameters: donor concentration (for electrical function), lattice constant (for mechanical stability), and electrically active donor concentration (for device performance). By independently controlling these parameters through compositional design, it achieves both low interface stress and adequate electrical functionality.
3Strength
If a transition layer is added to reduce cracking, then the structural integrity is improved, but the device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the semiconductor structure into multiple functional layers (first n-type layer, second n-type layer) with distinct donor concentrations. This segmentation allows each layer to be optimized for its specific function while collectively providing crack resistance through the graded structure.
Solution Approach 2:
The transition between layers is achieved through parameter changes in donor concentration and composition. Rather than adding a completely separate transition layer material, the patent uses gradual parameter changes within the gallium oxide-based semiconductor system to create a stress-gradient that prevents cracking.
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.