Lateral Power Devices with Shield Gate and Fixed Charge
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Solution Overview
Problem
Power MOSFETs face challenges in minimizing conduction power loss due to high specific on-resistance and increased gate-drain capacitance, which affects switching performance and efficiency.
Innovation Solution
Incorporating a shield electrode between the gate and drain in lateral power semiconductor devices with immobile net electrostatic charge, reducing parasitic Miller capacitance and enhancing switching performance by lowering gate-drain capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the active die area is increased to reduce specific on-resistance, then conduction performance improves, but device complexity and parasitic capacitance increase
Solution Approach 1:
The device transitions from a vertical architecture to a lateral architecture, changing the spatial dimension of current flow and electric field distribution. This dimensional change allows for reduced gate-drain overlap area, thereby reducing parasitic capacitance while maintaining effective conduction area through the lateral drift region
Solution Approach 2:
The shield electrode acts as a physical and electrical intermediary that reduces the parasitic capacitive coupling between the gate and drain terminals. By introducing this intermediate conductive element, the direct electric field interaction is minimized, reducing Miller charge effects
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 solution effectively reduces switching power losses and improves device efficiency by minimizing gate-drain capacitance without compromising device density or performance.
Implementation Method 1
a shield electrode which is at least partly interposed between the gate electrode and the drain to reduce capacitive coupling between the gate and the drain
Implementation Method 2
immobile net electrostatic charge, which has a polarity which tends to deplete a layer of the drift region
Data Source
AI summary
Lateral power devices where immobile electrostatic charge is emplaced in dielectric material adjoining the drift region. A shield gate is interposed between the gate electrode and the drain, to reduce the Miller charge. In some embodiments the gate electrode is a trench gate, and in such cases the shield electrode too is preferably vertically extended.