High Voltage Device With Segmented Gate And Sub-Gate
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Solution Overview
Problem
Conventional high voltage devices face a trade-off between breakdown voltage and on-resistance, where increasing breakdown voltage decreases on-resistance and operation speed, and vice versa, limiting their application range.
Innovation Solution
The design incorporates a semiconductor layer with a drift oxide region, well regions of different conductivity types, and sub-gates arranged in parallel with the gate, along with a conductive connection structure, to enhance breakdown voltage during OFF operation without increasing on-resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thickness of the isolation structure and drift oxide region is increased to increase withstand voltage, then breakdown voltage is improved, but on-resistance increases and operation speed decreases
Solution Approach 1:
The gate structure is segmented into a main gate and multiple sub-gates arranged in parallel. The sub-gates are positioned over the drift region and connected to the main gate through conductive structures. This segmentation allows the electric field to be distributed more effectively during OFF operation, increasing breakdown voltage without requiring increased oxide thickness, thereby maintaining low on-resistance and high operation speed during ON operation.
Solution Approach 2:
The patent introduces sub-gates that extend in the lateral direction parallel to the main gate, adding a dimensional aspect to the gate structure. This lateral extension of the gate control into the drift region allows for enhanced voltage control without increasing the vertical oxide thickness, thus improving breakdown voltage while maintaining the original on-resistance characteristics.
2Productivity
If the thickness of the isolation structure and drift oxide region is reduced to decrease on-resistance, then operation speed is improved, but breakdown voltage decreases
Solution Approach 1:
By segmenting the gate into main gate and sub-gates, the patent achieves enhanced breakdown voltage control through distributed electric field management. This allows the use of thinner oxide layers (reducing on-resistance) while the sub-gate structure compensates for the reduced dielectric strength, maintaining high breakdown voltage during OFF operation.
Solution Approach 2:
The patent changes the gate structure parameters by adding sub-gates with specific dimensions and positions. The sub-gates have a width and length that are optimized to provide the necessary electric field control. This parameter change allows the system to achieve high breakdown voltage with thinner oxide, enabling low on-resistance and high operation speed.
Data Source
AI summary
A high voltage device includes: a semiconductor layer, an isolation structure, a drift oxide region, a well, a body region, a gate, at least one sub-gate, a source, a drain and a conductive connection structure. The drift oxide region is located on a drift region in an operation region. The sub-gate is formed on the drift oxide region in the operation region. The sub-gate is a rectangle shape extending along a width direction, and in parallel with the gate. A conductive connection structure connects the gate and the sub-gate.