Semiconductor Trench Depth for Electric Field Relaxation
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Solution Overview
Problem
Conventional high breakdown voltage semiconductor devices fail to effectively relax the electric field in the junction termination region, resulting in an inability to achieve the desired breakdown voltage.
Innovation Solution
A semiconductor device structure is designed with trenches in the junction termination region, where the depth of the trenches is between 0.9 to 2.0 times the thickness of the second semiconductor region, and a specific capacitor ratio is maintained to control the electric field, allowing for effective electric field relaxation and high breakdown voltage achievement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the depth of trenches is increased to relax the electric field in the junction termination region, then the breakdown voltage improves, but the manufacturing complexity and cost increase
Solution Approach 1:
The patent applies parameter changes by optimizing the trench depth to a specific range (0.9 to 2.0 times the thickness of the second semiconductor region) rather than simply increasing depth indefinitely. This parameter optimization achieves effective electric field relaxation and high breakdown voltage while avoiding excessive manufacturing complexity associated with deeper trenches.
2Reliability
If the trench depth is made larger than the interval between trenches, then the electric field relaxation effect is enhanced, but the manufacturing precision requirements become more stringent
Solution Approach 1:
The patent changes the depth parameter to a specific range (0.9 to 2.0 times the thickness of the second semiconductor region) that balances electric field relaxation effectiveness with manufacturability. This parameter optimization ensures adequate relaxation effect while maintaining reasonable manufacturing precision requirements.
Data Source
AI summary
Provided is a semiconductor device which can relax the electric field in the junction termination region, and can achieve a high breakdown voltage.The semiconductor device includes an element region (51) and a junction termination region (52). The element region includes: a first semiconductor region (2) of a first conductivity type; a second semiconductor region (4) of a second conductivity type; a third semiconductor region (10) of the first conductivity type; a trench (35) passing through the second semiconductor region and the third semiconductor region and has a bottom surface which reaches the first semiconductor region (2); a gate insulating film (12) formed on the side surface and a bottom surface of the trench; and a gate electrode (8) embedded in the trench. The junction termination region includes: a terminal trench (55) formed in the depth direction from the top surface so as to surround the element region; a gate insulating film (12) formed on a sidewall and a bottom surface of the terminal trench; and a gate electrode (8) embedded in the terminal trench (55). The depth from the top surface of the second semiconductor region (4) to the bottom surface of the terminal trench (55) is 0.9 to 2.0 times the thickness of the second semiconductor region.