SiC MOSFET Schottky Diode Integration for Reliability
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Solution Overview
Problem
In semiconductor devices made of silicon carbide, the bipolar operation of parasitic diodes can generate crystal defects, increase on-resistance, and leakage current, and the incorporation of Schottky barrier diodes may lead to concerns about roll-off amount.
Innovation Solution
A semiconductor device structure is designed with specific semiconductor regions and electrodes, where the semiconductor regions 30 and 35 constitute both the base layer of the MOSFET and the contact layer with the source electrode of the Schottky barrier diode, allowing for commonality and integral formation, which reduces spacing, facilitates self-alignment, and controls the barrier height.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a Schottky barrier diode is incorporated to suppress bipolar operation, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent merges the base layer of the MOSFET and the contact layer of the Schottky barrier diode into a single integrated structure. This integration eliminates the need for separate layers while maintaining the functionality of both components, thereby suppressing bipolar operation without increasing device complexity
Solution Approach 2:
The merged layer serves multiple functions simultaneously: it acts as the base layer for the MOSFET and the contact layer for the Schottky barrier diode. This multi-functionality reduces the overall number of layers needed in the device structure while achieving the desired suppression of bipolar operation
2Ease of manufacture
If separate base layer and contact layer are used, then manufacturing flexibility is maintained, but manufacturing precision decreases
Solution Approach 1:
By merging the base layer and contact layer into a single integrated structure, the patent eliminates alignment issues between separate layers. The integrated formation process ensures precise positioning without requiring additional alignment steps, thereby improving manufacturing precision while maintaining ease of manufacture
3Productivity
If spacing between components is reduced, then device integration is improved, but electric field influence increases
Solution Approach 1:
The merged structure allows for reduced spacing between MOSFET and Schottky barrier diode components while the integrated design inherently manages electric field distribution. The unified structure enables better electric field control compared to separate components, allowing high integration without excessive electric field influence
Data Source
AI summary
According to an embodiment, a semiconductor device includes a substrate, a first semiconductor region, a second semiconductor region, a third semiconductor region, fourth semiconductor regions, and a first electrode. The second semiconductor region is provided on the first semiconductor region. The second semiconductor region includes a first portion and a second portion connected to the first portion in a first direction parallel to the first surface of the substrate. A conductivity type of the second semiconductor region is a second conductivity type. The first electrode is provided on the first portion of the second semiconductor region, the third semiconductor region, and the fourth semiconductor regions and is in contact with the first portion of the second semiconductor region.