Printable Semiconductor Structures for Flexible Electronics
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Solution Overview
Problem
Current methods for fabricating flexible electronic devices on plastic substrates face challenges such as incompatibility with traditional silicon-based technologies, limited electronic performance due to the use of amorphous or hybrid organic-inorganic semiconductors, and mechanical strain issues with rigid device components, leading to suboptimal field effect mobilities and reliability.
Innovation Solution
A high-yield fabrication platform using printable semiconductor elements with precise control over geometry, spatial orientation, and doping levels, enabling the transfer and assembly of microsized and nanosized semiconductor structures onto flexible substrates, including the use of bulk silicon wafers and smart-materials processing to achieve high performance comparable to single crystalline devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional high temperature processing methods are used for silicon-based semiconductors, then high electronic performance is achieved, but the plastic substrate melts or decomposes
Solution Approach 1:
The fabrication process is divided into separate stages: (1) fabricating semiconductor structures on a silicon wafer at high temperature, (2) creating recessed features and releasing the structures, (3) transferring the pre-fabricated semiconductor structures to the plastic substrate at low temperature. This segmentation allows high temperature processing to occur only on the silicon wafer, protecting the plastic substrate from thermal damage while still achieving high electronic performance.
Solution Approach 2:
A silicon wafer serves as an intermediary substrate for fabricating semiconductor structures before transfer to the final plastic substrate. The silicon wafer withstands high temperature processing, while the plastic substrate remains protected. The semiconductor structures are released from the silicon wafer and transferred to the plastic substrate, acting as a mediator that enables high temperature fabrication without exposing the plastic substrate to damaging temperatures.
2Adaptability or versatility
If amorphous or hybrid organic-inorganic semiconductors are used for flexibility, then compatibility with plastic substrates is achieved, but field effect mobility decreases significantly
Solution Approach 1:
High performance single crystalline silicon semiconductor structures are fabricated on a silicon wafer, then released and transferred (copied) onto the plastic substrate. This copying approach allows the benefits of single crystalline silicon (high field effect mobility) to be replicated on flexible plastic substrates without requiring the plastic substrate to withstand high temperature processing or chemical treatments.
Solution Approach 2:
The invention changes the processing temperature parameter from high temperature (>1000°C) to low temperature (<100°C) for the final assembly step. The semiconductor structures are pre-fabricated at high temperature on silicon, then transferred to the plastic substrate at low temperature, preserving the electrical properties achieved during high temperature fabrication while protecting the plastic substrate.
3Strength
If rigid device components are used on flexible substrates, then structural support is provided, but mechanical strain causes damage and performance degradation
Solution Approach 1:
The invention uses thin film semiconductor structures that are inherently flexible and can conform to the plastic substrate. These thin film structures provide the necessary structural support while maintaining flexibility, avoiding the mechanical strain and damage that would occur with rigid components on flexible substrates.
4Ease of manufacture
If solution processable materials are used for printing techniques, then fabrication cost is reduced, but electronic performance is limited
Solution Approach 1:
The fabrication process is segmented into two parts: (1) high precision semiconductor structure fabrication on silicon wafer using conventional techniques, (2) low cost transfer and assembly on plastic substrate using printing techniques. This segmentation allows the expensive high performance semiconductor structures to be manufactured using proven methods, while the low cost printing techniques are used only for the assembly and integration steps on the plastic substrate.
Data Source
AI summary
The present invention provides a high yield pathway for the fabrication, transfer and assembly of high quality printable semiconductor elements having selected physical dimensions, shapes, compositions and spatial orientations. The compositions and methods of the present invention provide high precision registered transfer and integration of arrays of microsized and/or nanosized semiconductor structures onto substrates, including large area substrates and/or flexible substrates. In addition, the present invention provides methods of making printable semiconductor elements from low cost bulk materials, such as bulk silicon wafers, and smart-materials processing strategies that enable a versatile and commercially attractive printing-based fabrication platform for making a broad range of functional semiconductor devices.