Semiconductor Light Emitting Device Intermediate Layer Adhesion
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Solution Overview
Problem
Semiconductor light emitting devices face reliability issues due to peeling between the wavelength conversion layer and semiconductor layers or resin units, caused by thermal expansion coefficient differences, leading to gaps and peeling, especially when using silicone-based resins for high dispersibility and transmittance.
Innovation Solution
Incorporating a thin intermediate layer with a material different from the wavelength conversion layer, such as silicon oxide or silicon nitride, to improve adhesion between the semiconductor layers, resin units, and wavelength conversion layers, and using a silane coupling agent to enhance bonding and reduce stress from thermal expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a wavelength conversion layer is directly formed on a semiconductor layer or resin unit, then the device structure is simple, but peeling occurs between layers due to thermal expansion coefficient differences
Solution Approach 1:
An intermediate layer is introduced between the wavelength conversion layer and the semiconductor layer or resin unit. This intermediate layer acts as a mediator that chemically bonds to both adjacent layers, suppressing peeling caused by thermal expansion coefficient differences. The intermediate layer includes a silane coupling agent that forms chemical bonds with the semiconductor layer, resin unit, and wavelength conversion layer, thereby improving interlayer adhesion without significantly increasing device complexity.
2Illumination intensity
If silicone-based resin is used for the wavelength conversion layer to achieve high dispersibility and transmittance, then optical performance is improved, but peeling is more likely to occur due to large thermal expansion coefficient difference
Solution Approach 1:
The intermediate layer serves as a buffer between the silicone-based resin wavelength conversion layer and the semiconductor layer. The silane coupling agent in the intermediate layer chemically bonds to both the semiconductor layer and the silicone-based resin, compensating for the large thermal expansion coefficient difference. This allows the use of silicone-based resin for its superior optical properties while preventing peeling through chemical bonding.
Solution Approach 2:
The intermediate layer changes the thermal expansion parameter profile by introducing a material with intermediate thermal expansion properties between the semiconductor layer and the silicone-based resin wavelength conversion layer. This gradual transition reduces thermal stress and prevents peeling while maintaining the high transmittance and dispersibility benefits of silicone-based resin.
3Ease of manufacture
If no intermediate layer is used, then manufacturing process is simpler, but gaps and peeling occur between layers
Solution Approach 1:
The intermediate layer with silane coupling agent provides chemical bonding capability between layers, ensuring high bonding quality. The silane coupling agent forms strong chemical bonds with the semiconductor layer, resin unit, and wavelength conversion layer, preventing gaps and peeling. This approach maintains manufacturing simplicity while dramatically improving layer bonding quality through chemical adhesion.
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
The intermediate layer significantly suppresses peeling between the wavelength conversion layer and semiconductor layers, resin units, and insulating layers, achieving higher adhesive strength and reliability by chemically bonding and matching thermal expansion coefficients, thereby improving the stability and uniformity of the light emission.
Implementation Method 1
The intermediate layer includes a silane coupling agent to enhance bonding and reduce stress from thermal expansion
Implementation Method 2
peeling between the wavelength conversion layer and semiconductor layers or resin units, caused by thermal expansion coefficient differences
Data Source
AI summary
According to one embodiment, a semiconductor light emitting device includes first and second columnar units, a wavelength conversion layer, a light emitting unit, a resin unit and an intermediate layer. The first columnar unit extends in a first direction. The second columnar unit is provided apart from the first columnar unit, and extends in the first direction. The wavelength conversion layer is provided apart from the first and second columnar units in the first direction. The light emitting unit includes first and second semiconductor layers, and a light emitting layer configured to emit a first light. The resin unit covers side surfaces along the first direction of the first and second columnar units and the light emitting unit, and a surface of the light emitting unit. The intermediate layer includes first and second portions, and has a thickness thinner than a peak wavelength of the first light.