Nitride Semiconductor Layer Substrate Separation via Light Absorption
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Solution Overview
Problem
The challenge in manufacturing semiconductor light emitting devices is the propensity of nitride semiconductor layers to crack and peel during the removal of the growth substrate, which hampers high light emission efficiency and reliability due to inadequate heat dissipation and substrate separation methods.
Innovation Solution
A method involving the formation of a nitride semiconductor layer on a substrate with unevenness, where a thin film of the same material is deposited on the inner wall of depressions, allowing for controlled light irradiation to separate the substrate while minimizing damage by varying light intensity across different portions of the layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the nitride semiconductor layer is bonded to a substrate with higher heat dissipation and the growth substrate is removed, then heat dissipation is improved, but the nitride semiconductor layer is prone to cracking and peeling
Solution Approach 1:
A thin film is formed on the growth substrate before bonding the nitride semiconductor layer. This preliminary action creates a buffer layer that prevents cracking and peeling during substrate removal while maintaining heat dissipation benefits
Solution Approach 2:
The thin film acts as an intermediary layer between the growth substrate and the nitride semiconductor layer. This mediator layer enables safe removal of the growth substrate by preventing direct stress transmission to the semiconductor layer
2Ease of manufacture
If light irradiation is used to separate the growth substrate from the nitride semiconductor layer, then separation is achieved, but the thin film absorbs light causing non-uniform intensity distribution
Solution Approach 1:
The thin film is formed with non-uniform thickness or material composition in different regions to compensate for light absorption. This creates local quality variations that result in uniform light intensity distribution across the semiconductor layer after accounting for absorption differences
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 effectively suppresses damage to the nitride semiconductor layer during substrate removal, enhancing light emission efficiency and reliability by ensuring controlled separation and reduced stress on the semiconductor layer.
Implementation Method 1
causing a thin film to absorb at least a part of the light so that an intensity of the light applied to a first portion is made lower than an intensity of the light applied to a second portion
Implementation Method 2
separating the first substrate from the nitride semiconductor layer by irradiating the nitride semiconductor layer with light via the first substrate
Data Source
AI summary
According to one embodiment, a method is disclosed for manufacturing a semiconductor light emitting device. The method can include forming a nitride semiconductor layer including a light emitting layer on a first substrate having an unevenness, bonding the nitride layer to a second substrate, and separating the first substrate from the nitride layer by irradiating the nitride layer with light. The forming the nitride layer includes leaving a cavity in a space inside a depression of the unevenness while forming a thin film on the depression. The film includes a same material as part of the nitride layer. The separating includes causing the film to absorb part of the light so that intensity of the light applied to a portion of the nitride layer facing the depression is made lower than intensity of the light applied to a portion facing a protrusion of the unevenness.