Silicon carbide mosfet with integrated gated diode for high surge current capability

Abstract

The invention relates to a silicon carbide MOSFET with high anti-surge current capability and integrated gate-controlled diode, which belongs to the technical field of power semiconductor devices. 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 during the bipolar conduction process of the PIN to form a recombination current. It will all be borne by the channel of the gated diode, which will greatly reduce the reliability of the gate oxide layer of the gated diode. In order to alleviate this problem, a parallel PNP BJT is integrated for the gated diode, and the reverse-biased PN junction is used to reduce the effective base region thickness and reduce the recombination of minority carriers in the base region, that is, reduce the generation of recombination current and alleviate the wave The current density of the channel region in the surge state improves the overall surge current resistance capability of the device.

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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