2D Material Transfer Patterning Without Grain Boundaries
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Solution Overview
Problem
When a two-dimensional (2D) material is grown on a large-area substrate, grain boundaries form at the boundaries of small regions, deteriorating the material's characteristics, and pattern processes further degrade these characteristics during transfer and device shaping.
Innovation Solution
A method involving forming a membrane forming pattern on a substrate, covering it with a membrane material layer, crystallizing it to create a protruding pattern, growing a 2D material pattern on this pattern, and transferring it to a transfer substrate, while maintaining the 2D material's characteristics by controlling its grain size and using it as a transfer template.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If 2D material is grown on a large-area substrate by CVD method, then crystallinity is improved, but grain boundaries are formed at domain boundaries which deteriorates characteristics
Solution Approach 1:
The patent divides the large-area substrate into multiple small-area substrates for separate 2D material growth. Each small substrate produces a single-grain 2D material without internal grain boundaries. These segmented 2D material pieces are then transferred and assembled on a target substrate to form a large-area device, thus achieving both high crystallinity and absence of grain boundaries.
Solution Approach 2:
The patent introduces a transfer substrate as an intermediary medium. The 2D material is first grown on a small-area substrate, then transferred to the transfer substrate, and finally moved to the target substrate. This intermediary transfer process enables the 2D material to maintain its single-grain structure while being positioned in a large-area device configuration.
2Shape
If pattern process is performed on 2D material to create device shape, then device structure is formed, but characteristics deteriorate during transfer and pattern processes
Solution Approach 1:
The patent performs the patterning process on the substrate before 2D material growth. The sacrificial layer is patterned into the desired device shape in advance, and the 2D material is subsequently grown to conform to this pre-defined pattern. This eliminates the need for post-growth patterning that would damage the 2D material.
Solution Approach 2:
Instead of the conventional approach of growing 2D material first and then patterning it, the patent inverts the sequence by patterning the sacrificial layer first and then growing the 2D material to match the pre-established pattern. This reverse approach protects the 2D material from damaging pattern 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
This method ensures the 2D material maintains excellent characteristics like crystallinity and allows for the formation of high-quality semiconductor devices without grain boundaries, enabling efficient transfer and integration into various electronic devices.
Implementation Method 1
forming a membrane having a protruding pattern by crystallizing the membrane material layer
Implementation Method 2
growing a 2D material on the membrane
Data Source
AI summary
A method of manufacturing a semiconductor device, including: forming a membrane forming pattern on a substrate; forming a membrane material layer on the substrate, wherein the membrane material layer covers the membrane forming pattern; forming a membrane having a protruding pattern by crystallizing the membrane material layer; forming a two-dimensional (2D) material pattern on the protruding pattern by growing a 2D material on the membrane; and transferring the 2D material pattern to a transfer substrate.