Fin Structure Width Step for Parasitic Capacitance Reduction
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Solution Overview
Problem
As semiconductor devices become highly integrated, transistors experience a short channel effect and reduced turn-on currents, leading to deteriorated characteristics, necessitating improvements in fin structure design to enhance reliability and integration.
Innovation Solution
The semiconductor device incorporates a fin component with a base part, an intermediate part, and a channel part, where the width of the intermediate part is less than the base part and greater than the channel part, with a gate electrode crossing over the fin component and a gate insulating layer between the channel part and the gate electrode, reducing the width stepwise to minimize parasitic capacitance and improve punch-through characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the fin structure uses a uniform width from base to channel, then the manufacturing process is simpler, but the parasitic capacitance increases and punch-through characteristics deteriorate
Solution Approach 1:
The fin structure is divided into three distinct segments: base part, intermediate part, and channel part, each with different width dimensions. This segmentation allows optimization of electrical characteristics (reducing parasitic capacitance and improving punch-through) while maintaining manufacturing feasibility through stepwise width reduction.
Solution Approach 2:
Different regions of the fin structure are given different width properties: the base part has the largest width for structural support, the intermediate part has reduced width for capacitance control, and the channel part has the smallest width for optimal electrical performance. This local differentiation resolves the contradiction between reliability and complexity.
2Speed
If the fin width is reduced to minimize parasitic capacitance, then the operating speed improves, but the manufacturing precision requirements increase
Solution Approach 1:
The fin width is segmented into three progressive stages (base > intermediate > channel) rather than a single abrupt reduction. This stepwise approach allows each segment to be controlled within achievable manufacturing tolerances while achieving the overall goal of reduced parasitic capacitance and improved operating speed.
Solution Approach 2:
The intermediate part width is set between the base and channel widths, providing a gradual transition that partially reduces the width to control capacitance without requiring the extreme precision needed for a direct base-to-channel width change. This partial action approach balances speed improvement with manufacturing feasibility.
3Reliability
If the gate electrode covers the intermediate part sidewalls, then the gate control is improved, but the parasitic capacitance increases
Solution Approach 1:
The gate electrode coverage is segmented: it covers the channel part sidewalls for effective gate control, but deliberately excludes coverage of the intermediate part sidewalls to minimize parasitic capacitance. This selective segmentation resolves the contradiction between gate control and capacitance reduction.
Solution Approach 2:
Different regions receive different gate coverage: the channel part receives full gate electrode coverage for optimal control, while the intermediate part sidewalls are excluded from coverage to reduce parasitic effects. This local differentiation optimizes both gate control and capacitance management.
Data Source
AI summary
A semiconductor device includes a fin portion protruding from a substrate. The fin portion includes a base part, an intermediate part on the base part, and a channel part on the intermediate part. A width of the intermediate part is less than a width of the base part and greater than a width of the channel part. A gate electrode coves both sidewalls and a top surface of the channel part, and a device isolation pattern covers both sidewalls of the base part and both sidewalls of the intermediate part.