Gallium Nitride Substrate Stripping for Reuse After Laser Lift-Off
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Solution Overview
Problem
The high cost of gallium nitride substrates limits the production of high-frequency, high-voltage, and high-power semiconductor devices due to their limited availability and expensive production.
Innovation Solution
A method for stripping gallium nitride substrates involves growing a gallium nitride epitaxial structure on the substrate, scanning and irradiating the substrate interior with a laser beam to create a decomposition layer, and separating the substrate at this layer to obtain a stripped substrate and a semiconductor device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gallium nitride substrates are directly used for growing epitaxial structures, then device performance is maintained, but substrate cost increases and production scale is limited
Solution Approach 1:
The patent applies the discarding and recovering principle by stripping the gallium nitride substrate after the epitaxial structure is grown and processed. The substrate is separated at a decomposition layer created by laser irradiation, allowing the expensive substrate to be recovered and reused for subsequent epitaxial growth, thereby reducing production costs while maintaining device performance
Solution Approach 2:
The patent extracts the epitaxial structure from the substrate by creating a decomposition layer within the substrate using laser beam irradiation. This allows selective separation of the epitaxial structure from the substrate at the decomposition layer, enabling substrate recovery while preserving the functional device structure
2Manufacturing precision
If laser beam with pulse width less than 10^-15 s is used to create decomposition layer, then substrate can be separated cleanly, but process complexity increases
Solution Approach 1:
The patent replaces mechanical separation methods with laser beam irradiation using ultra-short pulses (less than 10^-15 s). This optical method creates a decomposition layer within the substrate that enables clean separation without mechanical contact, achieving high precision separation while the pulsed nature of the laser simplifies the process control compared to continuous laser or mechanical methods
3Ease of manufacture
If substrate is stripped and reused, then production cost decreases, but substrate quality may deteriorate
Solution Approach 1:
The patent uses parameter changes in the laser beam (pulse width less than 10^-15 s, specific energy density) to create a decomposition layer at a controlled depth within the substrate. This precise control allows separation that preserves substrate quality by removing only the necessary portion while maintaining the structural integrity and crystalline quality of the remaining substrate for reuse
Solution Approach 2:
The patent performs preliminary laser irradiation to create a decomposition layer before separation. This preliminary action prepares the substrate by creating a defined separation plane that ensures clean detachment while preserving the quality of both the epitaxial structure and the substrate for subsequent reuse cycles
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 method reduces the cost of gallium nitride substrates by enabling their reuse and recycling, thereby lowering the overall production cost of semiconductor devices while maintaining high device performance.
Implementation Method 1
an interior of the gallium nitride substrate is scanned and irradiated via the gallium nitride epitaxial structure by a laser beam, so as to generate a decomposition layer in the gallium nitride substrate
Data Source
AI summary
Disclosed is a method for stripping a gallium nitride substrate, including: a gallium nitride substrate with a gallium nitride epitaxial structure directly grown on an upper surface thereof is acquired; an interior of the gallium nitride substrate is scanned and irradiated via the epitaxial structure by a laser beam, so as to generate a decomposition layer in the gallium nitride substrate, the laser beam being a laser having a pulse width on the order of less than 10−15 s, and a distance between the decomposition layer and the upper surface of the gallium nitride substrate being less than a thickness of the gallium nitride substrate; and the gallium nitride substrate is separated at the decomposition layer, so as to obtain a stripped gallium nitride substrate and a semiconductor device.