MOSFET Body Epitaxial Layering for Low Ron*Coff RF Switching
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Solution Overview
Problem
Existing MOSFET transistors face challenges in optimizing the trade-off between minimizing on-state resistance (Ron) and maximizing voltage RF Vmax for RF signal switching applications without increasing manufacturing complexity or cost, and in controlling the doping profile to achieve this balance.
Innovation Solution
A MOSFET transistor design featuring a body region with a heavily doped lower layer and a less heavily doped, non-intentionally doped epitaxial upper layer, where the upper layer is formed by epitaxial growth, allowing for improved conduction and reduced voltage resistance while maintaining high voltage RF Vmax, and optionally incorporating a diffusion stop layer to limit dopant diffusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the doping profile is optimized to improve RF performance, then manufacturing complexity increases
Solution Approach 1:
The body region is segmented into two distinct layers: a first doped layer formed by ion implantation or in-situ doping, and a second layer formed by epitaxial growth with lighter or non-intentional doping. This segmentation allows independent optimization of each layer's doping profile to achieve superior RF performance while using standard manufacturing processes.
Solution Approach 2:
The first doped layer is formed by ion implantation or in-situ doping before the epitaxial growth of the second layer. This preliminary doping action establishes the heavy doping region first, then the epitaxial process adds the lightly-doped or intrinsic layer on top, achieving the desired doping profile through sequential processing steps.
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 effectively minimizes the product Ron*Coff while maintaining high RF Vmax, reducing manufacturing complexity and cost, and improving the control over the doping profile, thus enhancing the performance of MOSFET transistors for RF applications.
Implementation Method 1
forming by epitaxial growth a second layer topping the first doped layer, the epitaxial growth being configured so that the second layer is less heavily doped than the first doped layer
Implementation Method 2
the first doped layer is a layer doped by ion implantation
Data Source
AI summary
A transistor includes a source region, a drain region and a body region arranged in a semiconductor layer. A gate region tops the body region. The body region includes a first doped layer and a second layer between the first doped layer and the gate region. The second layer is an epitaxial layer that is less heavily doped than the first doped layer.