Bow Adjustment Layer for GaN Substrate Bow Control
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Solution Overview
Problem
The fabrication of GaN-based semiconductor structures faces challenges due to substrate bow values that can lead to film cracking and affect the yield and quality of semiconductor devices, particularly in high-frequency, high-temperature, and high-voltage applications.
Innovation Solution
A substrate structure with a bow adjustment layer and a silicon layer is used to adjust the total bow value of the substrate to less than 50 μm, preventing film cracking and improving the uniformity and adhesion of subsequent GaN-based semiconductor layers, which are then deposited using a method that includes forming a substrate, a bow adjustment layer, and a silicon layer to achieve a flat structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a substrate is used for growing GaN-based semiconductor material, then the substrate provides mechanical support and mounting surface, but the substrate exhibits positive bow value that causes film cracking and reduces manufacturing precision
Solution Approach 1:
A bow adjustment layer is formed on the substrate surface before depositing the GaN-based semiconductor layer. This preliminary action creates a pre-compensated substrate structure with a negative bow value that counteracts the positive bow of the substrate, preventing film cracking during subsequent processing while providing a flat surface for high-precision manufacturing
Solution Approach 2:
The substrate structure's bow value parameter is actively adjusted by forming a bow adjustment layer with specific thickness and material properties. The layer's parameters (thickness, material composition) are optimized to transform the overall substrate bow from positive to negative, achieving a total bow value within the range of -50μm to 0μm, thereby resolving the contradiction between reliability and manufacturing precision
2Manufacturing precision
If the substrate bow value is not adjusted, then the fabrication process is simpler, but the GaN-based semiconductor layer exhibits poor adhesion and non-uniform growth
Solution Approach 1:
The bow adjustment layer is formed in advance on the substrate before any GaN-based semiconductor layers are deposited. This preliminary structuring ensures that the substrate surface has the optimal bow value and flatness required for uniform film growth and strong adhesion, eliminating the need for complex in-situ adjustments during the semiconductor layer fabrication process
Solution Approach 2:
The bow adjustment layer acts as an intermediary between the substrate and the GaN-based semiconductor layer. It mediates the mechanical stress and thermal expansion differences between the substrate and the semiconductor material, providing a stable, flat interface that ensures uniform growth and strong adhesion while isolating the semiconductor layer from the substrate's inherent bowing
Data Source
AI summary
A substrate structure and a method for fabricating a semiconductor structure including the substrate structure are provided. The substrate structure includes a substrate, a bow adjustment layer, and a silicon layer. The bow adjustment layer is on the top surface of the substrate. The silicon layer is on the bow adjustment layer. The substrate structure has a total bow value, and the total vow value is from −20 μm to −40 μm.