Engineered Substrates for Semiconductor Epitaxy
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional semiconductor substrate processing methods result in poor electronic characteristics and limited mechanical robustness, especially for plastic substrates which have limited chemical and heat tolerance and do not survive photo-lithographic processing, hindering the formation of high-quality, large-area semiconductor layers with desirable electron mobility.
Innovation Solution
An engineered substrate is created by assembling an array of seed structures with similar lattice constants and directional orientations on a target substrate, allowing for selective epitaxial growth of semiconductor materials with enhanced lattice matching and growth rates, using techniques like transfer printing and epitaxial growth methods such as molecular beam epitaxy, to form continuous, virtually single-crystal layers with improved mechanical robustness and tunable lattice parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If conventional coating methods (sputtering or spin-coating) are used to form semiconductor layers on large substrates, then large-area coverage is achieved, but electronic characteristics deteriorate
Solution Approach 1:
The substrate surface is segmented into multiple nucleation sites where separate epitaxial domains grow. Each domain originates from a seed structure and maintains high crystal quality, while collectively covering large substrate areas. This segmentation allows the system to achieve both large-area coverage and high electronic characteristics by treating the large substrate as an assembly of smaller high-quality regions.
2Adaptability or versatility
If plastic substrates are used for large-area applications, then flexibility and cost are improved, but chemical and heat tolerance deteriorate
Solution Approach 1:
Epitaxial semiconductor layers are grown on the plastic substrate before the substrate undergoes photo-lithographic processing. The epitaxial growth occurs at lower temperatures compatible with plastic substrates, and the resulting high-quality semiconductor layer provides the necessary chemical and heat tolerance for subsequent photo-lithographic steps, effectively transferring these properties from the inorganic epitaxial layer to the flexible plastic substrate system.
3Reliability
If photo-lithographic processing is applied to improve semiconductor layer performance, then electronic characteristics are improved, but plastic substrates cannot survive the processing
Solution Approach 1:
The epitaxial semiconductor layer is formed on the plastic substrate before photo-lithographic processing. This preliminary epitaxial growth creates a robust inorganic semiconductor layer that can withstand the chemical and thermal conditions of photo-lithography, while the plastic substrate provides mechanical flexibility throughout the process. The sequence of operations is critical: epitaxial growth first, then photo-lithography.
4Reliability
If conventional processing methods are used to improve electron mobility, then electronic characteristics are improved, but the performance remains worse than desirable
Solution Approach 1:
Conventional mechanical or chemical processing methods (sputtering, spin-coating, thermal treatment) are replaced with epitaxial growth techniques. Epitaxy provides atomic-level precision in forming semiconductor crystals, enabling superior electron mobility and performance that cannot be achieved through conventional processing. The epitaxial process allows for controlled incorporation of atoms in precise crystalline arrangements, achieving manufacturing precision at the atomic scale.
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 engineered substrate enables the formation of high-quality, continuous semiconductor layers with improved electronic characteristics and mechanical robustness, suitable for large-area applications like solar photovoltaics, while overcoming the limitations of conventional substrate processing methods.
Implementation Method 1
the assembling of the array of seed structures on the surface may be performed by transfer printing using an elastomer stamp from a source substrate to the surface of the target substrate
Implementation Method 2
Semiconductor materials are epitaxially grown selectively on the seed structures, such that a rate of growth of the semiconductor materials on the seed structures is substantially higher than a rate of growth of the semiconductor materials on regions of the surface
Data Source
AI summary
In a method for fabricating an engineered substrate for semiconductor epitaxy, an array of seed structures is assembled on a surface of the substrate. The seed structures in the array have substantially similar directional orientations of their crystal lattices, and are spatially separated from each other. Semiconductor materials are selectively epitaxially grown on the seed structures, such that a rate of growth of the semiconductor materials on the seed structures is substantially higher than a rate of growth of the semiconductor materials on regions of the surface. The semiconductor materials assume a lattice constant and directional orientation of crystal lattice that are substantially similar or identical to those of the seed structures. Related devices and methods are also discussed.