Semiconductor Epitaxial Transfer for Reusable LED Growth Substrates
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Solution Overview
Problem
Conventional methods for fabricating semiconductor light-emitting devices face challenges in selecting a suitable growth substrate that is not suitable for support, leading to reduced light-emitting efficiency and waste of the growth substrate, particularly in red light diodes where GaAs substrates are used, necessitating the development of efficient substrate transfer processes.
Innovation Solution
A method involving the formation of multiple epitaxial units on a substrate with adhesive layers and electrodes, followed by selective separation and transfer to support substrates using adhesive layers and sacrificial layers, allowing for the reuse of growth substrates and enhancing light-emitting efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If GaAs substrate is used as growth substrate for red light diode, then lattice constant matching is improved, but light-emitting efficiency deteriorates due to opacity to red light
Solution Approach 1:
The process is segmented into two distinct phases: growth phase using GaAs substrate for optimal lattice matching, and operation phase using transparent support substrate for optimal light emission. The semiconductor epitaxial structure is separated from the growth substrate and transferred to a transparent support substrate, allowing each substrate to fulfill its optimal function without compromise.
Solution Approach 2:
A transparent support substrate acts as an intermediary carrier that receives the semiconductor epitaxial structure from the GaAs growth substrate. This intermediary enables the transition from a substrate optimized for growth to a substrate optimized for light emission, resolving the contradiction between lattice matching and light transparency.
2Ease of manufacture
If growth substrate is removed and discarded, then substrate transfer is achieved, but material waste increases
Solution Approach 1:
Instead of discarding the GaAs growth substrate, the invention recovers and reuses it for growing additional semiconductor epitaxial structures. The growth substrate is cleaned and prepared after transferring the first epitaxial structure, then used to grow a second epitaxial structure, thereby recovering the substrate's value and eliminating waste.
Solution Approach 2:
The growth substrate serves itself by being reused for multiple growth cycles. After transferring the first semiconductor epitaxial structure, the substrate undergoes cleaning and preparation processes to restore its surface, enabling it to serve as a growth substrate again for producing additional epitaxial structures.
3Productivity
If multiple epitaxial structures are grown on single substrate, then productivity increases, but selective transfer complexity increases
Solution Approach 1:
Different regions of the growth substrate are assigned different functions through localized processing. First epitaxial structures in certain regions are prepared for transfer to transparent support substrates, while second epitaxial structures in other regions remain on the growth substrate for direct use. This local differentiation enables selective transfer without requiring complex global processing.
Solution Approach 2:
The production process is segmented into two independent streams: one for epitaxial structures intended for transfer (with associated transparent support substrates) and another for structures remaining on the growth substrate. This segmentation allows parallel processing and simplifies the overall transfer operation by treating different regions independently.
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 enables the reuse of growth substrates, improves light-emitting efficiency, and reduces environmental waste by effectively transferring semiconductor epitaxial structures while maintaining device performance.
Implementation Method 1
bonding the semiconductor epitaxial structure and the support substrate
Implementation Method 2
dissolving the growth substrate by etchant
Data Source
AI summary
A semiconductor light-emitting device comprises a substrate; a first adhesive layer on the substrate; multiple epitaxial units on the first adhesive layer; a second adhesive layer on the multiple epitaxial units; multiple first electrodes between the first adhesive layer and the multiple epitaxial units, and contacting the first adhesive layer and the multiple epitaxial units; and multiple second electrodes between the second adhesive layer and the multiple epitaxial units, and contacting the second adhesive layer and the multiple epitaxial units; wherein the multiple epitaxial units are totally separated.