Light-Emitting Device Substrate Removal via Laser Absorption
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Solution Overview
Problem
Conventional AlGaInP light-emitting devices suffer from low external quantum efficiency due to light absorption by the growth substrate and inadequate thermal conductivity, which limits their performance.
Innovation Solution
A method is developed to manufacture a light-emitting device by forming a light-absorbable layer and an illuminant epitaxial structure on a growth substrate, followed by removing the growth substrate using a laser beam with a wavelength greater than 1000 nm and subsequent wet etching with HCl and KOH, thereby preventing light absorption and improving thermal dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If GaAs growth substrate is used in AlGaInP light-emitting device, then the device structure is simple and easy to manufacture, but the external quantum efficiency is low due to light absorption by the substrate
Solution Approach 1:
The patent removes the GaAs growth substrate from the device structure through laser irradiation and wet etching processes. By extracting the problematic substrate that absorbs light, the invention eliminates the source of energy loss while maintaining the beneficial epitaxial structure grown on it, thereby resolving the contradiction between ease of manufacture and external quantum efficiency
Solution Approach 2:
The patent changes the optical parameters of the device by removing the GaAs substrate which has specific light absorption characteristics. This parameter change eliminates the absorption loss at the operating wavelength, improving external quantum efficiency while the manufacturing process remains feasible through the developed laser removal and etching techniques
2Ease of manufacture
If GaAs growth substrate is used in AlGaInP light-emitting device, then the device structure is simple, but the thermal conductivity is insufficient to dissipate heat effectively
Solution Approach 1:
The patent extracts the GaAs substrate which has inadequate thermal conductivity (44 W/m·°C). By removing this thermal bottleneck, the invention allows for replacement with substrates having superior thermal properties or direct heat dissipation paths, thereby resolving the contradiction between manufacturing simplicity and thermal management capability
Solution Approach 2:
The patent changes the thermal parameter of the device structure by eliminating the GaAs substrate layer. This enables improvement of thermal conductivity through substrate replacement or direct bonding to heat sinks, addressing the heat dissipation issue while maintaining ease of manufacture through the established laser removal and etching processes
3Reliability
If laser beam irradiation is used to remove the growth substrate, then the growth substrate can be removed effectively, but the process complexity increases
Solution Approach 1:
The patent applies preliminary action by first forming a light-absorbable layer on the GaAs substrate before laser removal. This preparatory step enables selective and controlled substrate removal by making the substrate absorbent to the laser wavelength, thereby achieving effective removal while managing process complexity through a systematic two-step approach
Solution Approach 2:
The patent introduces a light-absorbable layer as an intermediary between the laser beam and the GaAs substrate. This intermediary layer absorbs the laser energy and facilitates controlled substrate removal through subsequent wet etching, resolving the contradiction by enabling effective removal while maintaining process control and manageability
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 enhances the external quantum efficiency and thermal management of the light-emitting device, allowing for more efficient light emission and heat dissipation, thereby improving device performance.
Implementation Method 1
providing a laser beam and irradiating the second surface of the growth substrate, wherein the laser beam wavelength is greater than 1000 nm
Implementation Method 2
removing the growth substrate
Implementation Method 3
further removing the light-absorbable layer by wet etching with a solution of HCl and KOH
Data Source
AI summary
A light-emitting device and method for manufacturing the same are described. A method for manufacturing a light-emitting device comprising steps of: providing a growth substrate, wherein the growth substrate has a first surface and a second surface; forming a light-absorbable layer on the first surface of the growth substrate; forming an illuminant epitaxial structure on the light absorbable layer; providing a laser beam and irradiating the second surface of the growth substrate, wherein the laser beam wavelength is greater than 1000 nm; and removing the growth substrate.