Mesh Trench Gate Structure for Fast Switching and High Breakdown
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Solution Overview
Problem
Existing semiconductor devices with trench gate structures face challenges in balancing switching speed and breakdown voltage, as the concentration of electric fields can lead to increased parasitic capacitance and reduced breakdown voltage.
Innovation Solution
A semiconductor device with a mesh-patterned gate trench and separated field plate trenches, where the gate electrode and field plate electrodes are electrically connected to the source electrode, mitigating local electric field concentration and reducing parasitic capacitance while increasing breakdown voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a trench gate structure is used to increase switching speed, then the switching speed is improved, but the breakdown voltage decreases due to electric field concentration
Solution Approach 1:
The gate structure is divided into two separate electrodes: a bottom side electrode and an open side electrode. This segmentation allows independent control of electric fields at different locations, enabling the bottom electrode to maintain breakdown voltage while the open side electrode enables fast switching, thus resolving the contradiction between switching speed and breakdown voltage
Solution Approach 2:
Different regions of the gate structure are assigned different functions: the bottom side electrode is optimized for electrical connection and breakdown voltage maintenance, while the open side electrode is optimized for switching control. This local differentiation allows each region to perform its specific function optimally without compromising the other
2Ease of operation
If electric fields are concentrated to improve switching control, then switching control is improved, but parasitic capacitance increases
Solution Approach 1:
The gate electrode is segmented into bottom side and open side electrodes, allowing the electric field to be distributed across two separate regions rather than concentrated in one location. This reduces the peak electric field density and associated parasitic capacitance while maintaining effective switching control through coordinated operation of both electrodes
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 semiconductor device achieves enhanced breakdown voltage and reduced parasitic capacitance by distributing electric fields uniformly, improving operational efficiency and reliability.
Implementation Method 1
mitigating local electric field concentration and reducing parasitic capacitance while increasing breakdown voltage
Data Source
AI summary
A semiconductor device includes: a semiconductor layer; a gate trench that is formed in the semiconductor layer and arranged in a mesh pattern in plan view; a field plate trench that is formed in the semiconductor layer and that is surrounded by the gate trench in plan view and separated from the gate trench; an insulation layer formed on the semiconductor layer; a gate electrode arranged in the gate trench; a first field plate electrode arranged in the gate trench below a bottom surface of the gate electrode; a second field plate electrode arranged in the field plate trench; and a source electrode formed on the insulation layer. The first field plate electrode and the second field plate electrode are electrically connected to the source electrode.