Group III Nitride Light-Emitting Device In Concentration Preservation
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Solution Overview
Problem
Conventional methods for producing Group III nitride semiconductor light-emitting devices often result in a reduction of In concentration in the light-emitting layer, leading to decreased luminance and shifted emission wavelength, due to the use of hydrogen as a carrier gas which can etch In.
Innovation Solution
A method involving the formation of an n-side superlattice layer using nitrogen gas and a mixed gas with a controlled hydrogen ratio, allowing for the growth of a flat light-emitting layer without hydrogen as a carrier gas in the light-emitting layer formation, thereby maintaining In concentration and enhancing luminance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If hydrogen gas is used as a carrier gas during light-emitting layer formation, then flatness of the light-emitting layer is improved, but In concentration is reduced due to etching effect
Solution Approach 1:
The patent divides the semiconductor layer formation process into multiple stages: first forming an n-side superlattice layer with controlled hydrogen exposure to achieve flatness, then forming the light-emitting layer without hydrogen exposure to preserve In concentration. This segmentation allows each stage to have optimized conditions for its specific purpose.
Solution Approach 2:
The n-side superlattice layer is formed in advance as a preparatory step before forming the light-emitting layer. This preliminary action creates a flat surface foundation that enables subsequent light-emitting layer growth without requiring hydrogen exposure, thus preventing In etching while maintaining flatness.
2Reliability
If hydrogen gas is used as a carrier gas, then crystallinity of the semiconductor layer is improved, but luminance decreases due to In concentration reduction
Solution Approach 1:
The process is segmented into two distinct phases: Phase 1 uses hydrogen-containing carrier gas for forming the n-side superlattice layer to ensure good crystallinity and flatness; Phase 2 uses nitrogen-only carrier gas for forming the light-emitting layer to preserve In concentration and maximize luminance. Each phase is optimized for its specific requirement.
Solution Approach 2:
Different regions of the semiconductor structure are subjected to different carrier gas compositions: the n-side superlattice layer region receives hydrogen-containing gas for crystallinity enhancement, while the light-emitting layer region receives pure nitrogen gas to maintain high In concentration and luminance. This local quality differentiation resolves the contradiction between crystallinity and luminance.
3Manufacturing precision
If hydrogen gas is used as a carrier gas, then flatness is improved, but emission wavelength shifts due to In concentration variation
Solution Approach 1:
The n-side superlattice layer is formed in advance with controlled hydrogen exposure to establish a flat surface. This preliminary flatness achievement eliminates the need for subsequent hydrogen exposure during light-emitting layer formation, thereby preventing In concentration variation and maintaining stable emission wavelength.
Solution Approach 2:
The patent extracts hydrogen from the carrier gas composition during the light-emitting layer formation step, using only nitrogen gas. This extraction of hydrogen prevents the etching effect that would otherwise cause In concentration reduction and emission wavelength shifting, while the previously established flatness from the n-side superlattice layer is maintained.
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 approach results in a Group III nitride semiconductor light-emitting device with a high-flatness light-emitting layer, increasing output and maintaining In concentration, thus improving luminance without the adverse effects of hydrogen etching.
Implementation Method 1
the n-side superlattice layer having high flatness is formed through epitaxial growth
Implementation Method 2
In formation of the InGaN layer, nitrogen gas is supplied as a carrier gas. In formation of the second semiconductor layer, a first mixed gas formed of nitrogen gas and hydrogen gas is supplied as a carrier gas
Implementation Method 3
hydrogen sometimes removes In via an etching effect thereof
Data Source
AI summary
To provide a Group III nitride semiconductor light-emitting device production method, which is intended to grow a flat light-emitting layer without reducing the In concentration of the light-emitting layer. The method of the techniques includes an n-side superlattice layer formation step, in which an InGaN layer, a GaN layer disposed on the InGaN layer, and an n-type GaN layer disposed on the GaN layer are repeatedly formed. In formation of the InGaN layer, nitrogen gas is supplied as a carrier gas. In formation of the n-type GaN layer, a first mixed gas formed of nitrogen gas and hydrogen gas is supplied as a carrier gas. The first mixed gas has a hydrogen gas ratio by volume greater than 0% to 75% or less.