FinFET Composite Liner Surface Conversion Against Crystallization
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Solution Overview
Problem
The crystallization of amorphous silicon liners in FinFET devices during thermal processes leads to defects and constraints on low-temperature processing, affecting yield and critical dimension stability.
Innovation Solution
A surface treatment process converts an upper layer of the amorphous silicon liner into a dielectric conversion layer, such as oxide or nitride, using oxygen or ammonia-containing gases/plasma, preventing crystallization and allowing higher-temperature thermal processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If amorphous silicon liner is used in FinFET devices, then low-temperature processing is enabled, but crystallization during thermal processes causes defects and yield loss
Solution Approach 1:
A surface treatment process is performed on the amorphous silicon liner before subsequent thermal processing to convert the outer surface into a dielectric layer (oxide or nitride). This preliminary conversion prevents crystallization during later high-temperature steps, enabling the use of higher processing temperatures without causing defects or yield loss.
2Adaptability or versatility
If amorphous silicon liner is used, then processing flexibility is improved, but critical dimension stability deteriorates due to crystallization
Solution Approach 1:
The surface treatment process is applied in advance to convert the liner surface into a stable dielectric layer, preventing subsequent crystallization that would compromise critical dimension stability. This allows flexible thermal processing while maintaining precise dimensional control.
3Adaptability or versatility
If high-temperature thermal processes are performed, then processing options are expanded, but liner crystallization occurs causing defects
Solution Approach 1:
The amorphous silicon liner undergoes a surface treatment process before high-temperature processing to convert its outer surface into a thermally stable dielectric layer. This preliminary conversion eliminates the harmful crystallization effect during subsequent high-temperature steps, enabling expanded processing options without generating defects.
Solution Approach 2:
The surface treatment process changes the physical and chemical parameters of the liner surface, transforming it from amorphous silicon to a dielectric material with different thermal stability characteristics. This parameter change enables the liner to withstand high-temperature processing without crystallization.
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 enhances yield and maintains critical dimension stability by preventing liner crystallization, enabling wider processing choices and improved protection of semiconductor fins.
Implementation Method 1
A surface treatment process converts an upper layer of the amorphous silicon liner into a conversion layer, such as oxide or nitride
Implementation Method 2
using oxygen or ammonia-containing gases/plasma
Data Source
AI summary
A method of forming a semiconductor device includes forming a fin protruding above a substrate; forming a liner over the fin; performing a surface treatment process to convert an upper layer of the liner distal to the fin into a conversion layer, the conversion layer comprising an oxide or a nitride of the liner; forming isolation regions on opposing sides of the fin after the surface treatment process; forming a gate dielectric over the conversion layer after forming the isolation regions; and forming a gate electrode over the fin and over the gate dielectric.