Semiconductor Optical Device Thickness Reduction via InP Substrate Removal
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Solution Overview
Problem
Conventional semiconductor optical devices with InP substrates are limited in thickness reduction due to the brittleness of InP substrates, making it difficult to achieve smaller devices, especially for wearable applications, as grinding InP substrates thinner than 200 μm can lead to breakage.
Innovation Solution
A method involving the epitaxial growth of InGaAsP-based III-V semiconductor layers on an InP substrate followed by bonding to a thin Si substrate as a support, allowing for the removal of the InP substrate and subsequent grinding of the Si substrate to achieve a thickness of 80 μm to 200 μm, thereby reducing the overall device thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If InP substrate is ground to reduce thickness, then device thickness is reduced, but substrate strength deteriorates and breakage occurs
Solution Approach 1:
The substrate system is segmented into two parts: the InP growth substrate (used only during epitaxial growth and then removed) and the Si support substrate (which provides mechanical strength). This segmentation allows the device thickness to be reduced by removing the InP substrate while the Si substrate maintains structural integrity.
Solution Approach 2:
The Si substrate acts as an intermediary that temporarily supports the semiconductor laminate during manufacturing and then serves as the final support structure. It mediates between the need for thin device thickness and the requirement for sufficient substrate strength, enabling thickness reduction to 80-200 μm while preventing breakage.
2Length of moving object
If InP substrate thickness is reduced below 200 μm, then device thickness is reduced, but manufacturing reliability deteriorates due to breakage risk
Solution Approach 1:
The Si substrate is prepared in advance with appropriate thickness (80-200 μm) and bonding surfaces before the epitaxial growth process. This preliminary preparation ensures that the support structure is ready to provide mechanical strength throughout the manufacturing process, preventing breakage and ensuring manufacturing reliability.
Solution Approach 2:
The Si substrate serves as a reliable intermediary support that maintains manufacturing reliability during the epitaxial growth process and subsequent handling. Its sufficient thickness prevents breakage while allowing the final device to achieve reduced thickness after InP substrate removal.
3Stability of the object's composition
If InP substrate is used as support substrate, then lattice matching is achieved, but device thickness cannot be sufficiently reduced
Solution Approach 1:
The substrate function is segmented into two stages: during epitaxial growth, the InP substrate provides lattice matching; after growth, the InP substrate is removed and the Si substrate becomes the support. This segmentation resolves the contradiction by allowing lattice matching during manufacturing while enabling thickness reduction in the final device.
Solution Approach 2:
The InP substrate is discarded after serving its purpose of providing lattice matching during epitaxial growth. Its removal allows the device thickness to be reduced to 80-200 μm, while the Si substrate is recovered as the final support structure that maintains device integrity.
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 enables the manufacturing of semiconductor optical devices with reduced thickness, improved directivity of light emission, and increased light output power, addressing the limitations of traditional InP substrate-based devices.
Implementation Method 1
an InGaAsP-based III-V semiconductor layer such as an InP layer is epitaxially grown
Implementation Method 2
bonding the semiconductor laminate to a conductive support substrate formed from a Si substrate with at least a metal bonding layer therebetween
Data Source
AI summary
Provided is a method of manufacturing a semiconductor optical device, which makes it possible to reduce the thickness of a semiconductor optical device including InGaAsP-based III-V compound semiconductor layers containing at least In and P to a thickness smaller than that of conventional devices, and provide a semiconductor optical device. The method of manufacturing a semiconductor optical device includes a step of forming a semiconductor laminate on the InP growth substrate; a step of bonding the semiconductor laminate to the support substrate formed from a Si substrate, with at least the metal bonding layer therebetween; and a step of removing the InP growth substrate.