Multi-segment Isolation Structure for High Voltage MOS Device
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Solution Overview
Problem
High voltage metal oxide semiconductor devices face a trade-off between high breakdown voltage and low source-drain on-state resistance, as increasing breakdown voltage typically results in higher source-drain on-state resistance due to the size of the high voltage component.
Innovation Solution
A multi-segment isolation structure is implemented under the gate structure and beside the drift region to increase the conduction path length, thereby reducing the on-state resistance while maintaining high breakdown voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the high voltage component is designed to withstand a high breakdown voltage, then the breakdown voltage is increased, but the source-drain on-state resistance (Rdson) is increased
Solution Approach 1:
The isolation structure is divided into multiple segments (first isolation structure with multiple segments, second isolation structures) arranged in a specific pattern under the gate structure. This segmentation creates multiple current paths and increases the effective conduction path length without requiring a proportional increase in device area, thereby reducing on-state resistance while maintaining high breakdown voltage capability
Solution Approach 2:
The patent introduces a multi-dimensional isolation structure arrangement where isolation structures are positioned both laterally (bilateral sides) and vertically (under the gate structure at different depths). This spatial arrangement optimizes the electric field distribution and current conduction paths in multiple dimensions, achieving low on-state resistance without compromising breakdown voltage
Data Source
AI summary
A high voltage metal oxide semiconductor device with low on-state resistance is provided. A multi-segment isolation structure is arranged under a gate structure and beside a drift region for blocking the current from directly entering the drift region. Due to the multi-segment isolation structure, the path length from the body region to the drift region is increased. Consequently, as the breakdown voltage applied to the gate structure is increased, the on-state resistance is reduced.