High-Voltage MOSFET Drift Region Layout for Breakdown and Low Rds(on)
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional MOSFET devices face a challenge in achieving high breakdown voltage while maintaining low on-state resistance, as increasing breakdown voltage tends to increase on-state resistance due to parasitic resistances in high voltage applications.
Innovation Solution
The semiconductor device incorporates a high resistance region embedded in the drift region, specifically an amorphous semiconductor layer, which is strategically positioned between the source and drain regions to enhance breakdown voltage without compromising on-state resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the breakdown voltage is increased in a conventional MOSFET device, then the high voltage performance is improved, but the resistance in the on-state increases due to parasitic resistances
Solution Approach 1:
The drift region is segmented into multiple regions with different doping concentrations and resistance characteristics. Specifically, the device includes a first drift region with a first doping concentration and a second drift region with a second doping concentration, creating distinct functional zones that optimize both breakdown voltage and on-state resistance independently
Solution Approach 2:
Different regions of the drift zone are assigned different electrical properties to fulfill different functions. The first drift region has higher doping concentration for lower on-state resistance, while the second drift region has lower doping concentration for higher breakdown voltage. Additionally, high resistance regions are locally embedded at specific depths to provide field control without affecting overall resistance
2Reliability
If the drift region is optimized for high breakdown voltage, then the voltage handling capability is improved, but the on-state resistance increases
Solution Approach 1:
The doping concentration parameter is varied across different regions of the drift zone. The first drift region uses a first doping concentration optimized for low resistance, while the second drift region uses a second doping concentration optimized for high breakdown voltage. This parameter variation allows each region to contribute optimally to its intended function
Solution Approach 2:
The invention adds a vertical dimension to the drift region structure by embedding high resistance regions at specific depths below the surface. This depth dimension allows for field control and breakdown voltage enhancement without affecting the lateral current flow and on-state resistance
Data Source
AI summary
According to various embodiments, there is provided a MOSFET device. The MOSFET device may include a substrate; a first doped region disposed in the substrate; a second doped region disposed in the substrate, wherein the first doped region and the second doped region are laterally adjacent to each other; a third doped region disposed in the first doped region; a fourth doped region disposed in the second doped region; a gate disposed on the substrate, over the first and second doped regions, and between the third and fourth doped regions; and at least one high resistance region embedded in at least the second doped region, wherein the first doped region has a first conductivity type, wherein the second doped region, the third doped region, and the fourth doped region have a second conductivity type, wherein the first conductivity type and the second conductivity type are different.