Indium Phosphide Crystal Compressive Strain Slip Suppression
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Solution Overview
Problem
InP single crystals grown using existing methods often experience slip due to thermal stress during semiconductor layer growth, leading to device failure, as dislocations move easily in a limited sliding system and are observed as surface level differences.
Innovation Solution
The indium phosphide single crystal and substrate are designed with a compressive residual strain in the tangential direction of the outer circumferential portion, extending between specific inner and outer surfaces, to suppress slip occurrence by managing thermal stress through controlled temperature gradients and manufacturing processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing methods are used to grow InP single crystals, then crystal growth is achieved, but slip occurs due to thermal stress during semiconductor layer growth leading to device failure
Solution Approach 1:
The patent applies preliminary anti-action by introducing compressive residual stress in the outer circumferential portion of the InP single crystal before semiconductor layer growth. This pre-applied compressive stress counteracts the tensile thermal stress that will occur during subsequent heating, preventing dislocation movement and slip occurrence. The stress state is prepared in advance to neutralize the harmful thermal stress effects during device fabrication.
Solution Approach 2:
The patent changes the stress parameter from tensile to compressive in the outer circumferential portion of the crystal. By controlling the stress state through specific crystal growth conditions and post-growth treatments, the patent transforms the stress configuration to create a compressive residual stress field that prevents slip. This parameter change fundamentally alters the mechanical behavior of the crystal under thermal loading.
2Ease of manufacture
If thermal stress is applied during semiconductor layer growth, then layer formation is achieved, but dislocations move easily causing slip
Solution Approach 1:
The compressive residual stress is introduced as a preliminary counter-measure before thermal processing. This pre-established stress field acts as a barrier to dislocation movement during the subsequent semiconductor layer growth and thermal cycling, maintaining surface integrity while allowing normal manufacturing processes to proceed.
3Reliability
If the outer circumferential portion is modified to have compressive strain, then slip is suppressed, but crystal growth complexity increases
Solution Approach 1:
The patent applies local quality by modifying only the outer circumferential portion (5-10 mm from the surface) of the crystal while leaving the bulk material unchanged. This localized stress modification is achieved through controlled cooling rates or post-growth thermal treatment, creating a gradient stress distribution that suppresses slip at the critical surface region without requiring complete restructuring of the entire crystal growth process.
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 effectively reduces the occurrence of slip during semiconductor layer growth on the indium phosphide single crystal and substrate, enhancing the reliability of subsequent device fabrication by maintaining the compressive strain within optimal ranges.
Implementation Method 1
a residual strain in a tangential direction in an outer circumferential portion is a compressive strain
Data Source
AI summary
An indium phosphide single crystal including a straight body portion having a cylindrical shape, wherein a residual strain in a tangential direction in an outer circumferential portion is a compressive strain, the outer circumferential portion extending between an inner circumferential surface located 10 mm inward from an outer circumferential surface of the straight body portion toward a central axis and a location located 5 mm inward from the outer circumferential surface. There is also provided an indium phosphide single crystal substrate, wherein a residual strain in a tangential direction in an outer circumferential portion is a compressive strain, the outer circumferential portion extending between an inner circumference located 10 mm inward from an outer circumference toward a center and a location located 5 mm inward from the outer circumference.