Masked Epitaxial Semiconductor Structure for Dislocation Reduction
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Solution Overview
Problem
The epitaxial growth of III-V compound semiconductors often results in dislocations due to lattice mismatch and thermal expansion coefficient differences, leading to cracking and performance degradation in semiconductor devices.
Innovation Solution
A semiconductor structure and manufacturing method involving a substrate with a mask layer having a window that exposes the substrate, where the second substrate and epitaxial layer are grown, with the epitaxial layer located away from the first substrate, and the window's open end has an orthographic projection area less than the window's projection area on the substrate plane, terminating dislocations at the window's sidewall, reducing dislocation density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If epitaxial growth of III-V compound semiconductor is performed on a substrate, then high-speed, high-frequency, high-power and light-emitting electronic devices can be produced, but dislocation occurs due to lattice mismatch and thermal expansion coefficient difference
Solution Approach 1:
The patent divides the growth process into two distinct stages: first growing the second substrate material in the window region, then performing epitaxial growth of the III-V compound semiconductor layer on the second substrate. This segmentation allows each stage to be optimized independently, reducing dislocation propagation while maintaining device production capability
Solution Approach 2:
The second substrate acts as an intermediary layer between the first substrate and the III-V compound semiconductor. This intermediate layer with matched lattice constant reduces the direct lattice mismatch interaction, effectively lowering dislocation density while enabling high-quality epitaxial growth for device production
2Manufacturing precision
If film layer of III-V compound semiconductor reaches critical value, then complete epitaxial layer is formed, but cracking occurs resulting in degradation and effect loss of device performance
Solution Approach 1:
The second substrate serves as a buffer intermediary that absorbs thermal stress differences between the first substrate and the III-V compound semiconductor layer. This intermediary layer prevents stress accumulation that would otherwise cause cracking, enabling complete epitaxial layers to be formed without degradation
Solution Approach 2:
The patent changes the material parameter of the substrate by introducing a second substrate with a specific lattice constant that matches the III-V compound semiconductor. This parameter change reduces thermal expansion coefficient difference, preventing cracking while maintaining complete epitaxial layer formation
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
This approach effectively reduces dislocation density and improves device characteristics by terminating dislocations at the window's sidewall, preventing their continuation during growth, thus enhancing the performance and reliability of semiconductor devices.
Implementation Method 1
the window includes an open end, and an area of an orthographic projection of the open end on a plane where the first substrate is located is less than an area of an orthographic projection of the window on the plane where the first substrate is located... terminating dislocations at the window's sidewall
Implementation Method 2
a second substrate and a first epitaxial layer, where the second substrate and the first epitaxial layer are located in the window, and the first epitaxial layer is located on a side, away from the first substrate, of the second substrate
Data Source
AI summary
Disclosed are a semiconductor structure and a manufacturing method therefor. The semiconductor structure includes a first substrate; a mask layer, located on the first substrate; where the mask layer is provided with a window exposing the first substrate, the window includes an open end, and an area of an orthographic projection of the open end on a plane where the first substrate is located is less than an area of an orthographic projection of the window on the plane where the first substrate is located. When a first epitaxial layer is epitaxially grown on the second substrate, a dislocation of the first epitaxial layer terminates at the sidewall, the dislocation may not continue to extend along with a growth of the first epitaxial layer, so that a dislocation density of the semiconductor structure may be reduced, and device characteristic may be improved.