Hemispheric Metal Buffer Layer for Semiconductor Substrate Warpage
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Solution Overview
Problem
Semiconductor substrates with III-V nitride semiconductor layers face issues of substrate bow or warpage due to lattice mismatch, leading to stress and crystal defects, which deteriorate device characteristics and complicate manufacturing processes.
Innovation Solution
A semiconductor substrate with a discontinuous hemispheric metal layer formed on the substrate, followed by a nitride semiconductor layer, creates voids and a metal concentration gradient at the interface, effectively absorbing and relaxing strain, thereby minimizing substrate bow or warpage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a nitride semiconductor layer with thickness of 5 μm or more is formed on a heterogeneous substrate, then the semiconductor layer can provide sufficient functional thickness for device operation, but substrate bow or warpage occurs severely making subsequent manufacturing processes difficult
Solution Approach 1:
A buffer layer is introduced as an intermediary between the heterogeneous substrate and the nitride semiconductor layer. This buffer layer serves as a transition medium that gradually accommodates the lattice mismatch, allowing the formation of thick semiconductor layers (5 μm or more) while maintaining substrate planarity and enabling subsequent manufacturing processes
Solution Approach 2:
The lattice constant of the buffer layer is specifically controlled to be between 0.3 nm and 0.5 nm, creating a gradual transition in crystal structure parameters. This parameter change in the buffer layer enables the semiconductor layer to achieve sufficient thickness without causing severe substrate bow or warpage
2Ease of manufacture
If a nitride semiconductor layer is formed on a heterogeneous substrate, then the device can be fabricated, but stress and crystal defect occur due to lattice mismatch deteriorating device characteristics
Solution Approach 1:
The buffer layer's lattice constant is precisely controlled within the range of 0.3 nm to 0.5 nm, creating a gradual transition that reduces lattice mismatch. This parameter optimization allows device fabrication to proceed while minimizing stress and crystal defects, thereby improving device characteristics and reliability
Solution Approach 2:
The buffer layer provides localized quality improvement at the substrate-semiconductor interface by creating a gradual lattice transition zone. This local structural optimization reduces stress concentration and crystal defects at the interface, enabling reliable 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
This approach reduces substrate bow or warpage, facilitating easier handling and alignment during manufacturing, and minimizing product failure rates by absorbing strain and improving surface planarization.
Implementation Method 1
a semiconductor substrate having a hemispheric layer, which is capable of minimizing substrate bow or warpage by absorbing strain of interface
Data Source
AI summary
Provided is a semiconductor substrate and a method for manufacturing the same. The semiconductor substrate includes a substrate, a discontinuously formed hemispheric metal layer on the substrate, and a semiconductor layer on the hemispheric metal layer. A plurality of voids on the interface of the substrate and discontinuous hemisphere are formed to absorb or relax the stain of interface. Accordingly, even if a subsequent layer is relatively thickly formed on the substrate, substrate bow or warpage can be minimized.