Semiconductor Light Emitting Device With Composition Gradient Film
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Solution Overview
Problem
Existing semiconductor light emitting devices face challenges in achieving stable and reproducible light extraction efficiency due to variations in the angle of the slanted side surface of the mask film, leading to inconsistent device characteristics.
Innovation Solution
A semiconductor light emitting device is designed with a diffraction/scattering film having a side surface slanted with respect to the film thickness direction and a composition gradient, allowing for controlled etching rates and accurate slant control, thereby improving light extraction efficiency and reproducibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a photoresist mask with slanted side surface is formed by heat treatment to contract the photoresist, then the mask film can achieve a slanted side surface for light scattering, but the angle of the slanted surface varies across the wafer due to heat distribution variations, leading to poor reproducibility
Solution Approach 1:
The patent changes the material parameter of the mask film from photoresist to a temperature-stable material such as SiO2, Si3N4, or SiON. This material substitution eliminates sensitivity to heat distribution variations during processing, thereby maintaining consistent slanted side surface angles across the entire wafer and improving manufacturing precision and reproducibility.
2Illumination intensity
If a photoresist mask is used to form slanted side surfaces, then light extraction efficiency can be improved, but the variation in slant angle across the wafer causes variation in device characteristics
Solution Approach 1:
The patent changes the material parameter of the mask film to temperature-stable materials (SiO2, Si3N4, SiON) that are insensitive to heat distribution variations. This ensures uniform slanted side surface formation across the wafer, maintaining consistent light extraction efficiency and device characteristics, thereby improving reliability.
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 solution achieves excellent light extraction efficiency with high reproducibility by controlling the slant of the diffraction/scattering film's side surface, reducing total reflection and enhancing the overall performance of the semiconductor light emitting device.
Implementation Method 1
a diffraction/scattering film, which is formed between the light emitting layer and the substrate, for diffracting or scattering light generated at the light emitting layer
Implementation Method 2
a diffraction/scattering film, which is formed between the light emitting layer and the substrate, for diffracting or scattering light generated at the light emitting layer
Implementation Method 3
the diffraction/scattering film having a side surface slanted with respect to a film thickness direction thereof and having a composition gradient in the film thickness direction
Data Source
AI summary
The semiconductor device includes a substrate, a semiconductor layer which is formed on the substrate and includes a light emitting layer, and a diffraction/scattering film for diffracting or scattering light generated at the light emitting layer. The diffraction/scattering film is formed between the light emitting layer and the substrate, has a side surface slanted with respect to a film thickness direction thereof, and has a composition gradient in the film thickness direction.