FinFET Impurity Region Segmentation for Channel Precision
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Solution Overview
Problem
The miniaturization of FinFET devices poses challenges in forming a channel between the source and drain without defects, due to the difficulty in achieving the desired length and structure.
Innovation Solution
A semiconductor device design featuring a fin active region with protruding and recessed regions, where an epitaxial layer is placed in the recessed area, and an impurity region surrounds the side walls and bottom of the recessed region, sharing the same conductivity type as the epitaxial layer but with a different majority impurity, to facilitate effective channel formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the size of FinFET device is reduced to achieve high integration, then the integration density is improved, but the difficulty in forming a channel between source and drain increases
Solution Approach 1:
The source and drain regions are segmented into multiple portions (first through fourth portions) with different impurity concentrations. This segmentation allows each region to serve specific functions: higher concentration regions provide good electrical contact while lower concentration regions facilitate controlled channel formation, resolving the contradiction between miniaturization and channel formation precision
Solution Approach 2:
Different regions of the source and drain are assigned different impurity concentrations tailored to their local requirements. The first and fourth portions have higher impurity concentrations for electrical contact, while the second and third portions have lower concentrations to enable precise channel formation in the narrowed fin region, addressing the manufacturing precision challenge in miniaturized devices
2Productivity
If the fin width is narrowed to improve integration, then the device density is improved, but the channel length control becomes more difficult
Solution Approach 1:
The fin structure is divided into segments with varying impurity concentrations along its length. This segmentation simplifies the overall structure by using standardized doping regions rather than complex geometric modifications, enabling narrow fin width for high density while maintaining controllable channel characteristics through the graded impurity profile
Solution Approach 2:
The impurity concentration parameter is varied across different regions of the source and drain fins. By changing this material parameter rather than the geometric parameters, the patent achieves effective channel length control in narrow fins without increasing structural complexity, thus maintaining high device density
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 design enhances the reliability and control of the semiconductor device by preventing defects and improving the integration trend, allowing for precise channel formation and enhanced performance in high-integration semiconductor devices.
Implementation Method 1
An epitaxial layer may be disposed in the recessed region to have a height greater than a width
Implementation Method 2
An impurity region may be disposed in the fin active region, may surround side walls and a bottom of the recessed region
Data Source
AI summary
A semiconductor device having an impurity region is provided. The semiconductor device includes a fin active region having protruding regions and a recessed region between the protruding regions. Gate structures overlapping the protruding regions are disposed. An epitaxial layer is disposed in the recessed region to have a height greater than a width. An impurity region is disposed in the fin active region, surrounds side walls and a bottom of the recessed region, has the same conductivity type as a conductivity type of the epitaxial layer, and includes a majority impurity that is different from a majority impurity included in at least a portion of the epitaxial layer.