Anti-EMI SGT device

Abstract

The invention discloses an anti-EMI SGT device. The device comprises a substrate of a first conductive type, an epitaxial layer of the first conductive type which is positioned on the upper surface ofthe substrate of the first conductive type, a trench gate structure located in the epitaxial layer of the first conductive type, a trench source structure located above the side surface of the epitaxial layer of the first conductive type, a first dielectric layer and a heavily doped body region of the first conductive type located between the trench source structure and the epitaxial layer of thefirst conductive type, and a second dielectric layer located above the trench gate structure, wherein the trench gate structure comprises a gate trench, and a shielding gate and a polycrystalline silicon gate which are positioned in the gate trench; the trench source structure includes a source trench and a source metal located within the source trench. According to the device disclosed in the invention, the SGT source-drain capacitance Cds is increased, the switching oscillation is reduced, and therefore the voltage oscillation dv/dt failure possibility and EMI noise of the device are reduced.

Description

technical field [0001] The invention relates to the technical field of semiconductor devices, in particular to an anti-EMI SGT device. Background technique [0002] Shielded Gate Trench MOSFET (SGT-MOSFET for short) power devices have been widely used in the prior art. At the same time, MOSFETs (Metal Oxide Semiconductor Field Effect Transistors) are widely used in various fields such as switching power supplies, automotive electronics, and motor drives due to their advantages of large input resistance, easy driving, simple control, and high frequency characteristics. When it is used as a power switch tube to control energy flow and conversion, it works in a fast switching transition state, facing a high voltage oscillation dv / dt and current oscillation di / dt between the drain and source, on the one hand the high The voltage shock dv / dt is superimposed on the device, which is easy to cause the parasitic transistor to turn on and cause the device to fail; on the other hand, ...

AI Technical Summary

Problems solved by technology

When it is used as a power switch tube to control energy flow and conversion, it works in a fast switching transition state, facing a high voltage oscillation dv / dt and current oscillation di / dt between the drain and source, on the one hand the high The voltage shock dv / dt is superimposed on the device, which is easy to cause the parasitic transistor to turn on and cause the device to fail; on the other hand, the high voltage shock dv / dt is superimposed in the switching system, causing great electromagnetic interference, thus affecting the surrounding components and The equipment produces serious electromagnetic pollution

[0003] The existing SGT-MOSFET connects the shielded gate to the source potential, increases the switching speed and reduces the switching loss by reducing the Miller capacitance Cgd of the device, which inevitably leads to greater voltage oscillation dv / dt and Current oscillates di / dt, thereby increasing the possibility of device voltage oscillating dv / dt failure and EMI noise

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