Nitride Light Emitting Device Substrate Decomposition Prevention Layer
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Solution Overview
Problem
Current methods for growing single crystal nitride semiconductor materials on conductive substrates face challenges such as substrate deformation and decomposition at high temperatures, particularly with materials like zinc oxide, silicon, silicon germanium, and gallium arsenide, due to poor thermal conductivity and lattice mismatch, which hinders the production of high-quality nitride light-emitting devices.
Innovation Solution
A substrate decomposition prevention layer (SDPL) using boron nitride, silicon carbide, or silicon carbon nitride as a matrix is introduced to prevent substrate deformation, combined with specific layer structures and deposition methods like CVD, to facilitate the growth of high-quality nitride semiconductor materials on conductive substrates like zinc oxide, silicon, and gallium arsenide.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a conductive substrate such as zinc oxide, silicon, silicon germanium, or gallium arsenide is used for growing nitride semiconductor, then cost is reduced and thermal conductivity is improved, but the substrate deforms or decomposes at high temperature due to poor thermal stability and lattice mismatch
Solution Approach 1:
The patent introduces a substrate decomposition prevention layer as an intermediary between the conductive substrate and the nitride semiconductor layer. This intermediate layer protects the substrate from direct exposure to high-temperature processing conditions that cause decomposition, while still allowing thermal management and mechanical support functions to be maintained.
Solution Approach 2:
The patent employs a composite structure consisting of multiple layers with different material properties: the conductive substrate provides thermal management, the substrate decomposition prevention layer provides thermal stability, and the nitride semiconductor layer provides optoelectronic functionality. This composite approach allows each layer to optimize its specific function without compromising the overall system.
2Temperature
If a dielectric sapphire substrate is used for growing nitride semiconductor, then thermal stability is maintained, but thermal conductivity is poor leading to heat accumulation
Solution Approach 1:
The patent applies local quality by using different substrate materials for different functional requirements: the conductive substrate (silicon, zinc oxide, etc.) provides local thermal management at the substrate level, while the substrate decomposition prevention layer provides local thermal stability at the interface level. This localized functional differentiation resolves the contradiction between thermal conductivity and thermal stability.
3Ease of manufacture
If transparent conductive zinc oxide is used as substrate, then cost is reduced and electrical conductivity is improved, but the substrate is easily decomposed at high temperature under vacuum or reducing ambient
Solution Approach 1:
The substrate decomposition prevention layer serves as a protective intermediary between the cost-effective transparent conductive zinc oxide substrate and the harsh high-temperature vacuum or reducing ambient processing conditions. This intermediate layer prevents direct interaction between the zinc oxide substrate and the decomposing environment, enabling low-cost substrate usage without compromising processing reliability.
4Device complexity
If conventional substrates are used without decomposition prevention layer, then device structure is simple, but dislocation density is high reducing device quality
Solution Approach 1:
The patent creates a composite layered structure where the substrate decomposition prevention layer acts as a buffer between the substrate and the nitride semiconductor. This additional layer, while increasing structural complexity, dramatically reduces dislocation density by providing a graded transition zone that accommodates lattice mismatch and thermal expansion differences, thereby improving manufacturing precision.
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 allows for the growth of superior single crystal nitride semiconductors with reduced dislocation density and improved thermal stability, enabling the manufacture of high-quality nitride light-emitting devices with enhanced luminous efficiency, low operating voltage, and effective heat spreading.
Implementation Method 1
a substrate decomposition prevention layer (SDPL) including boron nitride (B—N), silicon carbide (Si—C), or silicon carbon nitride (Si—C—N) as a matrix
Implementation Method 2
deposition methods like CVD
Data Source
AI summary
A light-emitting device is provided with a substrate decomposition prevention layer using as a matrix at least one selected from the group consisting of boron nitride (B—N), silicon carbide (Si—C), and silicon carbon nitride (Si—C—N), and patterned into a predetermined shape; an n-type nitride clad layer formed on the substrate decomposition prevention layer; a nitride active layer formed on the n-type nitride clad layer; a p-type nitride clad layer formed on the nitride active layer; a p-type ohmic contact layer formed on the p-type nitride clad layer; a p-type electrode pad formed on the p-type ohmic contact layer; an n-type ohmic contact layer electrically connected to the n-type nitride clad layer by means of a patterned region of the substrate decomposition prevention layer; and an n-type electrode pad formed beneath the n-type ohmic contact layer.