Silicon Layer Transfer via Photochemical Oxide Removal
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The challenge lies in transferring a high-temperature silicon layer to a flexible substrate without damaging the single crystalline silicon layer, as conventional methods like forming holes or patterning into a ribbon are not suitable for obtaining an intact, large-area silicon layer.
Innovation Solution
A method involving an SOI substrate where an etchant or its vapor is applied and light is irradiated to remove the oxide layer, allowing the silicon layer to be transferred to another substrate without physical or chemical damage, using HF or BOE as etchants and visible light with wavelengths between 380 to 750 nanometers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single crystalline silicon layer is deposited on a substrate and holes are formed or patterned into ribbon to remove intermediate oxide layer, then the oxide layer can be removed, but the silicon layer is easily damaged and cannot obtain an intact large-area silicon layer
Solution Approach 1:
The patent introduces light as an intermediary to activate the etchant. The etchant itself serves as the mediator that selectively removes the oxide layer when activated by light, allowing non-contact oxidation removal without mechanical damage to the silicon layer.
Solution Approach 2:
The patent replaces mechanical methods (drilling holes, patterning into ribbon) with a photochemical method. Light irradiation activates the etchant to chemically remove the oxide layer, substituting mechanical intervention with a chemical process that preserves silicon layer integrity.
2Manufacturing precision
If silicon layer is deposited at conventional high temperature (approximately 1,400 degrees centigrade), then high-quality single crystalline silicon layer can be obtained, but it cannot be directly applied to flexible substrate with poor heat resistance
Solution Approach 1:
The patent separates the silicon layer deposition process from the substrate application process. The silicon layer is deposited on a suitable substrate at high temperature, then the intermediate oxide layer is removed, enabling transfer to the flexible substrate at low temperature.
Solution Approach 2:
The patent introduces an intermediate substrate and an intermediate oxide layer as mediators. The silicon layer is first formed on an intermediate substrate at high temperature, then the oxide layer removal enables transfer to the final flexible substrate at low temperature, protecting the flexible substrate from heat damage.
3Ease of manufacture
If light is irradiated to SOI substrate while etchant is applied, then etchant permeability through silicon layer increases and oxide layer is removed, but requires additional equipment and process steps
Solution Approach 1:
The patent makes the etchant self-activating through light irradiation. The etchant automatically becomes permeable and active when exposed to light, removing the need for complex external activation systems or multiple processing steps.
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 enables the transfer of a large-area, intact single crystalline silicon layer to flexible substrates, overcoming heat-related limitations and enabling the fabrication of high-purity silicon devices like MOS transistors and thin film transistors without damaging the silicon layer.
Implementation Method 1
irradiating a light to the SOI substrate while applying an etchant or vapor of the etchant to the SOI substrate, thereby increasing a permeability of the etchant or the vapor of the etchant through the silicon layer
Data Source
AI summary
A method for forming a silicon layer according to inventive concept comprises: preparing an SOI substrate; applying an etchant or vapor of the etchant to the SOI substrate; and irradiating a light to the SOI substrate.