Dual Drain MOSFET With Segmented Doping To Reduce Short Channel Effects
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Solution Overview
Problem
The challenge in semiconductor device manufacturing is to reduce the size of metal-oxide-semiconductor field-effect transistors (MOSFETs) while minimizing performance and reliability issues associated with short channel effects, which conventional techniques often fail to adequately address.
Innovation Solution
The implementation of a field effect transistor (FET) design with a substrate having distinct conductivity types and doping concentrations in its source and drain portions, along with a dual drain structure, which allows for independent biasing and adjustment of threshold voltage and sub-threshold swing, and is fabricated using conventional technology with minimal equipment modifications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If MOSFET size is reduced to increase circuit density, then more devices can be fabricated on each wafer, but short channel effects deteriorate device performance and reliability
Solution Approach 1:
The drain region is segmented into two separate drain portions with different doping concentrations. The first drain portion has a higher doping concentration while the second drain portion has a lower doping concentration, allowing each segment to address different aspects of short channel effects and enable independent biasing for optimized device performance
Solution Approach 2:
Different regions of the drain are assigned different doping concentrations to create local variations in electrical properties. The first drain portion with higher doping concentration is positioned to handle specific electrical stress, while the second drain portion with lower doping concentration manages other aspects of current flow, allowing localized optimization of device characteristics
2Ease of manufacture
If conventional fabrication processes are used for scaled MOSFETs, then manufacturing simplicity is maintained, but process limitations prevent further size reduction
Solution Approach 1:
The dual drain structure with different doping concentrations is incorporated into the MOSFET design before the final scaling step. This preliminary structural preparation allows the device to benefit from improved short channel effect control in subsequent fabrication steps without requiring fundamental process changes
Solution Approach 2:
Instead of solely relying on reducing channel length in one dimension, the invention introduces complexity in the doping concentration dimension by creating two drain portions with different doping levels. This dimensional approach to problem-solving allows performance improvement without proportionally increasing fabrication complexity
Data Source
AI summary
System and method for metal-oxide-semiconductor field effect transistor. In a specific embodiment, the invention provides a field effect transistor (FET), which includes a substrate material, the substrate material being characterized by a first conductivity type, the substrate material including a first portion, a second portion, and a third portion, the third portion being positioned between the first portion and the second portion. The FET also includes a source portion positioned within the first portion, the source portion being characterized by a second conductivity type, the second conductivity type being opposite of the first conductivity type. A first drain portion is positioned within second portion and characterized by the second conductivity type and a first doping concentration. A second drain portion is positioned within the second portion and is characterized by the second conductivity type and a second doping concentration, the second doping concentration being different from the first doping concentration.