Super Junction MOSFET Avalanche Current Routing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Super junction MOSFETs with a trench gate structure face challenges in improving avalanche capability due to parasitic bipolar transistor action caused by avalanche current flow through the source electrode.
Innovation Solution
The semiconductor device incorporates a super junction structure with trench gate structures, a p-type body region, and specific impurity concentrations to direct avalanche current flow away from the source region, preventing parasitic bipolar transistor action by routing the current through a p+-type region and p-type body region, thereby enhancing avalanche capability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the avalanche current flows through the source electrode in a trench gate structure, then the device structure is simplified, but parasitic bipolar transistor action occurs reducing avalanche capability
Solution Approach 1:
The patent introduces a p-type body region as an intermediary layer between the channel layer and the source region. This intermediary layer with controlled impurity concentration (1×10^16 to 1×10^18 atoms/cm³) modifies the current flow path during avalanche breakdown, preventing direct current flow through the source electrode that would cause parasitic bipolar transistor action. The body region acts as a mediator that redirects the avalanche current, improving reliability without significantly increasing device complexity
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 improves avalanche capability while maintaining high breakdown voltage and low on-resistance, preventing parasitic bipolar transistor action and optimizing electric field distribution.
Implementation Method 1
a depletion layer spreads out from each p-n junction between the n-type drift region and the p-type compartment region into the n-type drift region
Implementation Method 2
avalanche breakdown occurs directly below a trench gate. Therefore, an avalanche current flows to a source electrode by way of a channel layer on an outer side wall of a trench and a source layer
Data Source
AI summary
A semiconductor device includes a semiconductor substrate and a super junction structure on the substrate. The super junction structure is constructed with p-type and n-type column regions that are alternately arranged. A p-type channel layer is formed to a surface of the super junction structure. A trench gate structure is formed to the n-type column region. An n+-type source region is formed to a surface of the channel layer near the trench structure. A p+-type region is formed to the surface of the channel layer between adjacent n+-type source regions. A p-type body region is formed in the channel layer between adjacent trench gate structures and in contact with the p+-type region. Avalanche current is caused to flow from the body region to a source electrode via the p+-type region without passing through the n+-type source region.