SiC MOSFET Super Junction Structure for Lower RDS(on)
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Solution Overview
Problem
Conventional SiC MOSFETs face high drain-source on-resistance (RDS(on)) due to the high contribution of the drift region, which limits their performance and increases manufacturing costs despite advancements in channel mobility and other parameters.
Innovation Solution
Implementing a super junction (SJ) structure in SiC MOSFETs by using high-energy ion implantation to create P-pillar regions, balancing charge distribution and reducing N-type doping concentration in the drift region, thereby reducing RDS(on) without compromising breakdown voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional SiC MOSFET structure is used, then manufacturing cost is reduced by using standard processes, but drain-source on-resistance (RDS(on)) is high due to drift region contribution
Solution Approach 1:
The drift region is segmented into multiple regions with different doping concentrations: a first drift region with higher doping concentration and a second drift region with lower doping concentration. This segmentation allows the device to achieve low RDS(on)) through the first drift region while maintaining high breakdown voltage through the second drift region, resolving the contradiction between manufacturing cost and device performance.
Solution Approach 2:
Different regions of the drift region are assigned different doping concentrations to optimize local functions. The first drift region has higher doping concentration for low resistance, while the second drift region has lower doping concentration for high breakdown voltage. This local quality differentiation enables the device to simultaneously achieve low RDS(on)) and high reliability without requiring expensive advanced 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 SJ structure reduces RDS(on) by approximately 30-40% and enhances breakdown voltage capability, addressing the limitations of conventional SiC MOSFETs and lowering manufacturing costs.
Implementation Method 1
A first ion implantation of P-type dopants is performed on the epitaxial layer to form a low-doped first carrier region and a second carrier region
Data Source
AI summary
The present invention involves a power device and a manufacturing method thereof. The method comprising steps of providing a semiconductor substrate, growing an epitaxial layer on the semiconductor substrate, forming an insulating layer on the epitaxial layer, forming a metal mask layer on the insulating layer, and performing an ion implantation process from above the metal mask layer on the epitaxial layer. The metal mask layer includes an ion implantation blocking region and an ion implantation penetration region.