Germanium GAA Channel Structure for Scaled MOSFET Mobility
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Solution Overview
Problem
The scale-down of metal-oxide-semiconductor field-effect transistors (MOSFETs) in semiconductor devices leads to deterioration in operation characteristics, necessitating improvements in mobility properties and integration density.
Innovation Solution
A semiconductor device design featuring a channel pattern with semiconductor patterns made of germanium, a gate electrode extending between these patterns, and gate spacers, along with a method involving sacrificial pattern removal and thermal treatment to form germanium-based semiconductor patterns, enhancing carrier mobility and integration density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If MOSFETs are scaled down to meet increasing demand for smaller pattern size, then device integration density is improved, but operation characteristics deteriorate
Solution Approach 1:
The patent changes the material composition of the channel pattern from conventional silicon to germanium-based semiconductor material. This parameter change in material composition improves carrier mobility and maintains operation characteristics even as device size is reduced for higher integration density.
Solution Approach 2:
The patent uses germanium-silicon alloy (SiGe) as a composite material in the channel pattern, combining the advantages of both germanium (high carrier mobility) and silicon (complementary device characteristics). This composite material approach allows maintaining reliable operation characteristics while enabling device scaling for higher integration density.
2Ease of manufacture
If conventional silicon-based channel patterns are used, then manufacturing process is simple, but carrier mobility is limited
Solution Approach 1:
The patent changes the material parameter from silicon to germanium-based semiconductor material in the channel pattern. This parameter change significantly improves carrier mobility while the manufacturing process remains compatible with existing semiconductor fabrication techniques through thermal treatment and layer formation methods.
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
Improves carrier mobility and facilitates high integration density in semiconductor devices by using germanium-based semiconductor patterns and a gate-all-around-type field effect transistor structure.
Implementation Method 1
performing a thermal treatment process on the plurality of preliminary semiconductor patterns provided with the germanium layer to convert the plurality of preliminary semiconductor patterns to a plurality of semiconductor patterns
Data Source
AI summary
A semiconductor device includes, on a substrate, a channel pattern including semiconductor patterns, which are spaced apart from each other in a first direction perpendicular to a top surface of the substrate, a gate electrode on the channel pattern, the gate electrode disposed on an uppermost semiconductor pattern of the semiconductor patterns and extended into regions between the semiconductor patterns, and a pair of gate spacers disposed on the uppermost semiconductor pattern to cover opposite side surfaces of the gate electrode, respectively. Each semiconductor pattern includes germanium. Each semiconductor pattern includes a pair of first portions vertically overlapped with the pair of gate spacers and a second portion between the pair of first portions. A thickness, in the first direction, of a pair of first portions of the uppermost semiconductor pattern is larger than a thickness, in the first direction, of the second portion of the uppermost semiconductor pattern.