SOI MOSFET Embedded Doping Region for Floating Body Effect Reduction
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Solution Overview
Problem
Silicon-on-insulator (SOI) MOSFET devices experience significant floating body effects, particularly in NMOS devices, leading to decreased voltage between source and drain regions, which adversely affect performance.
Innovation Solution
Incorporating an embedded region of a first conductivity type directly under the channel region in the SOI semiconductor device, acting as a hole sink to alleviate floating body effects, with specific doping concentrations and thicknesses optimized to minimize these effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an embedded region of the first conductivity type is added under the channel region, then floating body effects are reduced, but device structure becomes more complex
Solution Approach 1:
The semiconductor device is segmented into distinct functional regions: the embedded region of the first conductivity type is separated from the source/drain regions of the second conductivity type, with each segment performing a specific function. The embedded region specifically addresses floating body effects while source/drain regions handle carrier injection, thereby reducing mutual interference and optimizing overall device performance
Solution Approach 2:
The embedded region acts as an intermediary element between the channel region and the substrate, serving as a hole sink that mediates the floating body effect. This intermediate structure absorbs excess holes generated in the channel, preventing them from accumulating and causing voltage fluctuations, thus stabilizing device operation without requiring fundamental changes to the basic MOSFET structure
2Reliability
If the embedded region is made with higher doping concentration, then hole sinking capability is improved, but manufacturing precision requirements increase
Solution Approach 1:
The doping concentration of the embedded region is optimized to be higher than that of the source/drain regions (first conductivity type vs. second conductivity type), creating a strong electric field that enhances hole sinking capability. This parameter change allows the embedded region to effectively attract and capture holes generated in the channel, improving floating body effect reduction while maintaining manufacturability through standard doping processes
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
The embedded region effectively reduces floating body effects by acting as a hole sink, improving the operational performance of SOI MOSFET devices by stabilizing voltage between source and drain regions.
Implementation Method 1
an embedded region of the first conductivity type disposed in the top semiconductor layer and directly under the channel region. The embedded region acts as a hole sink to alleviate or avoid floating body effects
Data Source
AI summary
An SOI semiconductor device includes a substrate, a buried oxide layer disposed on the substrate, a top semiconductor layer disposed on the buried oxide layer, a source doping region and a drain doping region in the top semiconductor layer, a channel region between the source doping region and the drain doping region in the top semiconductor layer, a gate electrode on the channel region, and an embedded doping region disposed in the top semiconductor layer and directly under the channel region. The embedded doping region acts as a hole sink to alleviate or avoid floating body effects.