FinFET Germanium Doping Mitigates Short Channel Effects
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Solution Overview
Problem
Increased integration density in semiconductor devices leads to a short channel effect in field effect transistors, which affects their performance and reliability.
Innovation Solution
A semiconductor device design featuring a fin structure with a sacrificial layer and an active layer, where the concentration of germanium is higher in certain regions to reduce the short channel effect, and a gate insulating layer and gate electrode are disposed to cover the active layer, enhancing gate controllability and current capability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If integration density is increased, then device integration density is improved, but short channel effect occurs
Solution Approach 1:
The patent transitions from a planar transistor structure to a three-dimensional FinFET structure with a fin extending vertically from the substrate. This dimensional change increases the effective channel width without increasing the footprint area, thereby improving integration density while maintaining gate control over the channel to mitigate short channel effects.
Solution Approach 2:
The patent employs selective germanium doping in specific regions of the active layer, with higher germanium concentration in first and second regions compared to the third region. This local variation in material composition optimizes carrier mobility and electrical characteristics in different areas of the device, improving overall performance while managing short channel effects.
2Power
If germanium concentration is increased in first and second regions, then operating current is improved, but manufacturing complexity increases
Solution Approach 1:
The patent implements spatially varying germanium concentrations in the active layer, with higher Ge content in source/drain adjacent regions (first and second regions) and lower Ge content in the central region (third region). This localized material differentiation enhances carrier mobility where needed while simplifying the overall doping profile compared to uniform high germanium content throughout the active layer.
Data Source
AI summary
Provided is a semiconductor device. The semiconductor device includes a fin disposed on a substrate along a first direction. A sacrificial layer is disposed on the fin. An active layer is disposed on the sacrificial layer. A gate insulating layer and a gate electrode are disposed along a second direction intersecting the first direction. The gate insulating layer covers substantially entire top, side and bottom surfaces of the active layer. A source or drain region is disposed on at least one side of the gate electrode on the substrate. A first concentration of germanium in a first region and a second region of the active layer is higher than a second concentration of germanium in a third region disposed between the first region and the second region.