Anti-dv/dt SGT device

Abstract

The invention discloses an anti-dv / dt SGT device, which comprises a substrate of a first conductive type, an epitaxial layer of the first conductive type positioned on the upper surface of the substrate of the first conductive type, a trench located in the epitaxial layer of the first conductive type, a first dielectric layer, a lightly doped body region of the first conductive type located at thebottom part of the trench, a heavily doped body region of the first conductive type located on the periphery of the first dielectric layer, source electrode metal located above the side face of the epitaxial layer of the first conductive type, a second dielectric layer located on the upper surface of the trench, and a polycrystalline silicon gate and a shielding gate which are positioned in the trench. According to the anti-dv / dt SGT device, the drain-source capacitance Cds can be increased, and the switching oscillation is reduced, so that the possibility of voltage oscillation dv / dt failureof the device is reduced.

Description

technical field [0001] The invention relates to the technical field of semiconductor devices, in particular to a dv / dt-resistant 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 ...

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 The current oscillates di / dt, thereby increasing the possibility of device voltage oscillating dv / dt failure

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