Silicon carbide MOSFET of integrated grid-controlled diode with high surge current resistance

Abstract

The invention relates to a silicon carbide MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor) of an integrated grid control diode with high surge current resistance, and belongs to the technical field of power semiconductor devices. As the withstand voltage of a silicon carbide power device is higher and higher, a drift region is thicker and thicker, so that more and more minority carriers of a PIN are compounded in the drift region to form a compound current in a bipolar conduction process, the compound current is completely borne by a channel of a grid-controlled diode, and the reliability of a gate oxide layer of the grid-controlled diode is greatly reduced. In order to alleviate the problem, a parallel PNP BJT is integrated for a grid-controlled diode, the thickness of an effective base region is reduced by using a reverse biased PN junction, and the recombination of minority carriers in the base region is reduced, that is, the generation of recombination current is reduced, the current density of a channel region in a surge state is alleviated, and the surge current resistance of the whole device is improved.

Description

technical field [0001] The invention belongs to the technical field of power semiconductor devices, in particular to a silicon carbide MOSFET with integrated gate-controlled diode with high anti-surge current capability. Background technique [0002] The wide-bandgap semiconductor material SiC is an ideal material for the preparation of high-voltage power electronic devices. Compared with Si material, SiC material has a high breakdown electric field strength (4×10 6 V / cm), high carrier saturation drift velocity (2×10 7 cm / s), high thermal conductivity, good thermal stability, etc., so it is especially suitable for high-power, high-voltage, high-temperature and radiation-resistant electronic devices. [0003] SiC VDMOS is a commonly used device in SiC power devices. Compared with bipolar devices, since SiCVDMOS has no charge storage effect, it has better frequency characteristics and lower switching losses. At the same time, the wide band gap of SiC material enables the ope...

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Problems solved by technology

However, as the withstand voltage of silicon carbide power devices becomes higher and higher, the drift region becomes thicker and thicker, which makes more and more minority carriers recombine in the drift region to form a recombination current during the bipolar conduction process of the PIN. The current will all be borne by the channel of the gate-controlled diode, which will greatly reduce the reliability of the gate oxide layer of the gate-controlled diode

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