SiC MOSFET (Metal Oxide Semiconductor Field Effect Transistor) device of integrated gate protection structure

Abstract

The invention relates to the technical field of semiconductors and particularly relates to a SiC MOSFET device with an integrated gate protection structure. The device sequentially comprises a scribing groove region, a terminal region, a p + main ring, a gate runway and a source runway on the p + main ring, an active region formed by connecting a plurality of primitive cell structures in parallel,and pressing block metal of a source and a gate on the active region from the edge to the center, the device is characterized in that two or more polycrystalline silicon pn diode structures which arereversely connected in series are integrated between the gate runway and the source runway to serve as a gate protection structure of the device. According to the device, the gate protection device is integrated on the chip, when the gate voltage of the device exceeds the maximum allowable voltage, the gate protection device is broken down, so the gate source voltage is clamped at the maximum allowable voltage, and the MOS gate medium is protected from bearing high voltage.

Description

technical field [0001] The invention relates to the technical field of semiconductors, in particular to a SiC MOSFET device with an integrated gate protection structure. Background technique [0002] Compared with Si, the wide bandgap semiconductor material SiC has about 3 times the bandgap width, 10 times the critical breakdown electric field strength, and 3 times the thermal conductivity. Therefore, SiC devices have the advantages of higher withstand voltage, higher operating frequency and higher temperature resistance compared with Si devices. Both theory and practice have confirmed that SiC MOSFET has a switching frequency of more than 10 and better switching efficiency than Si-based IGBT, so SiC devices will have a very large application field and market. [0003] There are two kinds of atoms, Si and C, in the SiC material, so the thermal oxidation mechanism is much more complicated than that of the Si material, making SiC / SiO in the SiCMOS structure 2 The interface s...

AI Technical Summary

Problems solved by technology

However, in actual circuit applications, there are often some disturbances in current and voltage, such as sudden opening and closing of loads, circuit failures, external electromagnetic interference, etc., which may cause voltage fluctuations in the gate. If the gate voltage The fluctuation range exceeds the allowable range of the gate voltage, which will reduce the life and reliability of the gate, and even directly cause the breakdown of the gate dielectric

In order to avoid this phenomenon and protect the gate, a gate protection circuit is often set in the drive circuit in circuit applications, which not only increases the cost, but also makes the drive circuit complex and fragile

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