Semiconductor Groove Gate Electric Field Control
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Solution Overview
Problem
Conventional semiconductor devices with gate electrodes in grooves suffer from electric field concentration at the outer corner portions of the grooves, leading to reduced breakdown voltage due to the absence of a base region outside the outermost grooves.
Innovation Solution
A semiconductor device is designed with a second conductive type impurity region formed adjacent to the lead-out portion and extending downward beyond the lower end of the groove, creating a depletion layer that suppresses electric field concentration and allows for current path control, thereby reducing the risk of breakdown voltage reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If no base region is formed outside the outermost grooves, then the device structure is simpler, but electric field concentration occurs at the outer corner portions of the grooves leading to reduced breakdown voltage
Solution Approach 1:
The invention applies local quality by forming a base region only at specific locations (outside the outermost grooves) rather than uniformly throughout the device. This localized base region is positioned precisely where electric field concentration occurs, providing targeted electric field relaxation without requiring a complete base region across the entire device structure, thus maintaining relative simplicity while improving breakdown voltage.
Solution Approach 2:
The base region acts as an intermediary element between the drain drift region and the outermost grooves. It mediates the electric field distribution by introducing a depletion layer that relaxes the concentrated electric field at the outer corner portions of the grooves, thereby preventing breakdown without fundamentally altering the overall device architecture.
2Productivity
If the device area is reduced, then productivity increases, but electric field concentration cannot be effectively suppressed
Solution Approach 1:
The invention addresses electric field suppression in a reduced area by transitioning to a different dimensional approach - forming a base region that extends in the lateral dimension outside the outermost grooves. This lateral extension of the base region provides effective electric field relaxation without increasing the vertical device height or requiring proportional increases in other dimensions, enabling area reduction while maintaining reliability.
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 impurity region effectively disperses electric field concentration, inhibits current path attraction to lead-out portions, and allows for a reduced device area while maintaining high breakdown voltage.
Implementation Method 1
a depletion layer is formed on the p-n junction portion... the impurity region for current path control formed adjacent to the lead-out portion downward beyond at least a lower end of the groove
Data Source
AI summary
A semiconductor device includes a gate electrode formed through an insulating film in a groove having a first side surface adjacent to a source region and a base region, and a second conductive type first impurity region formed adjacent to a second side surface of the groove between the groove and a lead-out portion of a drain region existing below the base region so as to extend downward beyond a lower end of the groove.