Indium Nitride Well Layer Hydrogen Control for Laser Efficiency
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Solution Overview
Problem
Conventional methods fail to sufficiently suppress indium segregation and non-uniformity in nitride semiconductor well layers, leading to high threshold current density and increased photoluminescence half width in semiconductor laser devices, which hampers their commercialization and efficiency.
Innovation Solution
A semiconductor light-emitting device with an indium-containing well layer having a hydrogen concentration greater than the n-type cladding layer and less than the p-type cladding layer, manufactured using a hydrogen-containing carrier gas to control indium segregation and surface morphology, thereby reducing threshold current density and photoluminescence half width.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the indium concentration in the gas phase is increased during crystal growth to increase the light-emitting wavelength, then the light-emitting wavelength increases, but indium segregates on the surface of the well layer, creating non-light-emitting regions and significantly lowering the light-emitting efficiency
Solution Approach 1:
The patent applies preliminary action by performing a first crystal growth step to form the well layer with high indium content, then performing a second crystal growth step to form an overlayer before indium segregation occurs. This sequential approach prevents the harmful segregation effect while maintaining the desired light-emitting wavelength by establishing the proper structure in advance.
Solution Approach 2:
The patent segments the crystal growth process into two distinct steps: a first step for forming the well layer with high indium concentration to achieve the desired wavelength, and a second step for forming an overlayer to prevent indium segregation. This segmentation allows each step to optimize for its specific function without the negative effects of the other.
2Manufacturing precision
If the growth is discontinued and carrier gas containing ammonia, nitrogen and hydrogen is supplied to remove segregated indium, then indium segregation is suppressed, but the surface morphology deteriorates due to hydrogen etching effect
Solution Approach 1:
The patent prevents indium segregation in the first place by forming the well layer structure before segregation can occur, eliminating the need for subsequent removal processes that would damage the surface morphology. The overlayer is formed as a preliminary protective measure during the crystal growth process itself.
Solution Approach 2:
The patent converts the potential harm of continued crystal growth (which would cause indium segregation) into a benefit by immediately forming a protective overlayer that prevents segregation while avoiding the harmful hydrogen etching effect of discontinuing growth and supplying carrier gas.
3Reliability
If indium content non-uniformity is suppressed to reduce photoluminescence half width, then laser oscillation becomes easier to achieve, but the manufacturing process becomes more complex
Solution Approach 1:
The patent segments the crystal growth into two simple sequential steps with clearly defined parameters, making the process easier to control and reproduce. Each step has specific duration and condition parameters that can be independently optimized, reducing overall manufacturing complexity while achieving uniform indium distribution.
Solution Approach 2:
The patent uses parameter changes by controlling the relative durations of the first and second crystal growth steps, along with their respective temperature and pressure conditions, to achieve uniform indium content. By adjusting these parameters, the photoluminescence half width is reduced and laser oscillation capability is improved without requiring complex manufacturing processes.
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 effectively suppresses indium segregation and non-uniformity, resulting in a semiconductor light-emitting device with a low threshold current density and narrower photoluminescence half width, facilitating easier laser oscillation and improved light-emitting efficiency.
Implementation Method 1
it is necessary to increase the proportion of hydrogen supplied as the carrier gas, the surface morphology deteriorates due to the hydrogen etching effect
Implementation Method 2
a carrier gas containing an ammonia gas, a nitrogen gas and a hydrogen gas is supplied to remove segregated indium
Implementation Method 3
the active layer having a quantum well structure
Data Source
AI summary
A semiconductor light-emitting device includes an n-type cladding layer formed on a substrate, an active layer formed on the n-type cladding layer and including a well layer and a barrier layer, and a p-type cladding layer formed on the active layer. The well layer is made of an indium-containing nitride semiconductor, and has a hydrogen concentration greater than that of the n-type cladding layer and less than that of the p-type cladding layer.