In1-xAlxP Clad Layer Strain Control for Optical Semiconductor Doping
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Variation in dopant diffusion and doping concentration in optical semiconductor devices affects manufacturing yield and reliability, particularly due to instability in dopant material supply and diffusion processes, which is challenging to control with conventional processing methods.
Innovation Solution
Incorporating In1-xAlxP layers with specific Al composition and strain levels in the clad layer of optical semiconductor devices to stabilize dopant concentration and reduce variation, ensuring the Al composition is above the doping concentration and strain within critical limits to maintain pseudomorphic growth and minimize lattice mismatch dislocations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional processing methods are used for doping, then manufacturing simplicity is maintained, but doping concentration variation increases and manufacturing yield deteriorates
Solution Approach 1:
The patent applies parameter changes by carefully controlling the Al composition (x) in In1-xAlxP layers and the strain amount in the clad layer to specific ranges. By adjusting these parameters, the diffusion constant of p-type dopant is stabilized, resulting in uniform doping concentration throughout the active layer while maintaining manufacturing feasibility.
Solution Approach 2:
The patent uses composite material structure by incorporating In1-xAlxP layers within the clad layer. This composite structure combines InP and InAlP materials to achieve both mechanical stability (strain control) and chemical stability (dopant diffusion control), thereby improving doping uniformity without excessive complexity.
2Quantity of substance
If dopant material supply is increased to ensure sufficient doping, then doping concentration is improved, but supply stability decreases and variation increases
Solution Approach 1:
The patent changes the physical and chemical parameters of the clad layer by incorporating In1-xAlxP layers with specific Al composition and controlled strain. This modification stabilizes the diffusion constant of dopant atoms, ensuring consistent dopant concentration without requiring variations in supply quantity, thus improving supply stability.
3Stability of the object's composition
If higher Al composition is used in In1-xAlxP layers to stabilize dopant concentration, then doping stability is improved, but strain amount increases and dislocation occurs
Solution Approach 1:
The patent optimizes the Al composition (x) parameter within a specific range (0 < x ≤ 0.3) and controls the strain amount to be within ±0.003. This parameter optimization achieves dopant concentration stability while preventing excessive strain that would cause lattice mismatch dislocation.
Solution Approach 2:
The patent applies local quality by creating In1-xAlxP layers with specific Al composition only in regions where dopant diffusion control is needed, rather than uniformly throughout the entire structure. This localized approach stabilizes doping where necessary while minimizing overall strain and dislocation risk.
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 significantly stabilizes the doping concentration of p-type dopants, improves manufacturing yield, and reduces costs by enhancing material utilization efficiency and device reliability while maintaining high-quality device characteristics.
Implementation Method 1
Variation in diffusion of p-type dopant from the p-type semiconductor layer or the like toward the active layer affects the device characteristics and reliability
Implementation Method 2
the absolute value of the average strain amount of the whole of the clad layer of the second conductivity type is equal to or less than the absolute value of a critical strain amount obtained by Matthews' relational expression
Data Source
AI summary
An optical semiconductor device includes an InP substrate; an active layer disposed above the InP substrate; a n-type semiconductor layer disposed below the active layer; and a p-type clad layer disposed above the active layer, wherein the p-type clad layer includes one or more p-type In1-xAlxP layers, the Al composition x of each of the one or more p-type In1-xAlxP layers is equal to or greater than a value corresponding to the doping concentration of a p-type dopant, and the absolute value of the average strain amount of the whole of the p-type clad layer is equal to or less than the absolute value of a critical strain amount obtained by Matthews' relational expression, using the entire layer thickness of the whole of the p-type clad layer as a critical layer thickness.