Transistor Drain Extension Segmentation for Low Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
MOS power transistors in automotive and industrial electronics face challenges in achieving low switch-on resistance, high breakdown voltage in the switch-off state, and reducing gate-drain capacitance, particularly the gate-drain capacitance between the gate electrode and the drain electrode.
Innovation Solution
A semiconductor device with a transistor structure featuring a channel region and a drain extension region, where the drain extension region comprises a core portion doped with a first conductivity type and a cover portion doped with a second conductivity type, adjacent to the sidewalls and top side of a ridge, along with a gate electrode and a field plate, to optimize conductivity and capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the drain extension region is doped with a single conductivity type, then the manufacturing process is simple, but the switch-on resistance is high and conductivity is poor
Solution Approach 1:
The drain extension region is segmented into two distinct doped portions: a first doped portion with first conductivity type and a second doped portion with second conductivity type. This segmentation allows each portion to contribute differently to the electrical characteristics, reducing overall resistance while maintaining manufacturability through sequential doping processes.
Solution Approach 2:
Different regions of the drain extension region are assigned different doping characteristics. The first doped portion has higher doping concentration for low resistance, while the second doped portion has lower doping concentration for optimal electrical field distribution. This local differentiation optimizes both conductivity and reliability.
2Ease of operation
If the gate-drain overlap area is increased to improve transistor control, then gate control capability improves, but gate-drain capacitance increases
Solution Approach 1:
The drain extension region exhibits spatially varying doping characteristics, with the first doped portion having higher concentration and the second portion having lower concentration. This local quality variation allows the structure to maintain effective gate control while managing capacitance through optimized charge distribution in different regions.
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 configuration enhances the transistor's conductivity during switch-on and maintains high breakdown voltage during switch-off, while reducing gate-drain capacitance, thereby improving overall performance and efficiency.
Implementation Method 1
The channel region is doped with dopants of a first conductivity type, and the drain extension region is doped with dopants of a second conductivity type
Data Source
AI summary
A transistor is formed by forming a ridge including a first ridge portion and a second ridge portion in a semiconductor substrate, the ridge extending along a first direction, forming a source region, a drain region, a channel region, a drain extension region and a gate electrode adjacent to the channel region, in the ridge, doping the channel region with dopants of a first conductivity type, and doping the source region and the drain region with dopants of a second conductivity type. Forming the drain extension region includes forming a core portion doped with the first conductivity type in the second ridge portion, and forming the drain extension region further includes forming a cover portion doped with the second conductivity type, the cover portion being formed so as to be adjacent to at least one or two sidewalls of the second ridge portion.