Single Crystalline Silicon Layer Formation via Selective Deposition
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Solution Overview
Problem
Conventional methods for forming single crystalline silicon layers face temperature limitations and substrate damage, leading to inferior mobility and uniformity, particularly when using high-temperature processes like the smart-cut process, and result in uneven surfaces that hinder the achievement of high crystallinity.
Innovation Solution
A method involving the formation of a silicon nitride layer, an insulating layer with a hole, deposition of a first silicon layer, and a second silicon layer, followed by thermal crystallization using an excimer laser annealing process, which allows for the creation of a high-crystallinity single crystalline silicon layer with a planar surface, suitable for thin film transistors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high-temperature processes (smart-cut process) are used to form single crystalline silicon, then crystallinity is improved, but substrate damage and thermal shock occur
Solution Approach 1:
The invention changes the temperature parameter from conventional high-temperature (900-1100°C) processing to low-temperature (600-750°C) processing. This is achieved by using a silicon nitride layer as a crystallization catalyst and excimer laser annealing to provide localized energy, enabling single crystalline silicon formation without subjecting the substrate to damaging high temperatures
Solution Approach 2:
The invention replaces the conventional thermal field (high-temperature annealing) with a combination of chemical catalysis (silicon nitride layer) and localized laser energy (excimer laser). This substitution allows crystallization to occur at lower temperatures, avoiding substrate damage while maintaining high crystallinity
2Manufacturing precision
If conventional deposition methods are used to form silicon layers, then material coverage is achieved, but surface flatness deteriorates
Solution Approach 1:
The silicon nitride layer serves as an intermediary that facilitates selective silicon deposition. It acts as a catalyst that enables silicon atoms to deposit preferentially on its surface, automatically forming a planar structure. This intermediary layer simplifies the deposition process while ensuring high surface flatness without requiring complex control mechanisms
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 enables the fabrication of high-quality single crystalline silicon layers with improved surface flatness and crystallinity, suitable for high-performance thin film transistors and other silicon-based devices, while accommodating plastic or glass substrates without thermal shock damage.
Implementation Method 1
crystallizing the second silicon layer using a thermal process
Implementation Method 2
crystallizing the second silicon layer using a thermal process
Implementation Method 3
depositing a first silicon layer on an exposed bottom of the hole using a selective deposition process
Data Source
AI summary
Provided are a method of forming a single crystalline silicon layer, a structure including the same, and method of fabricating a thin film transistor (“TFT”) using the same. The method of forming the single crystalline silicon layer includes forming a silicon nitride layer on a substrate, forming an insulating layer on the silicon nitride layer, forming a hole in the insulating layer to a predetermined dimension, depositing a first silicon layer on an exposed bottom of the hole using a selective deposition process, depositing a second silicon layer on the insulating layer and the first silicon layer formed in the hole, and crystallizing the second silicon layer using a thermal process. In this method, a high-quality single crystalline silicon layer can be obtained.