Silicon carbide diode with low turn-on voltage and low on resistance and manufacturing method

Abstract

The invention provides a silicon carbide diode with low turn-on voltage and low on resistance and a manufacturing method thereof. The silicon carbide diode comprises a cathode metal electrode, an N +substrate above the cathode metal electrode and an N-drift region above the N + substrate, a P-type shielding buried layer arranged above the N-drift region; a P + ohmic contact region arranged in theP-type shielding buried layer, an anode metal electrode arranged above the P + ohmic contact region, a trench gate dielectric layer arranged above the P-type shielding buried layer, a polysilicon trench gate arranged in the trench gate dielectric layer, an N+ source regions arranged between the trench gate dielectric layers, a plane gate dielectric layer arranged above the N + source regions, anda polysilicon plane gate arranged in the plane gate dielectric layer. The anode metal electrode covers the trench gate dielectric layer, the polysilicon trench gate, the N+ source region, the plane gate dielectric layer and the polysilicon plane gate. According to the invention, the three-channel accumulation type channel MOSFET and the JFET are connected in series to form the super-barrier diode, and the silicon carbide diode has the characteristics of low turn-on voltage, small on-resistance, high reverse withstand voltage, small leakage current and the like.

Description

Technical field [0001] The invention belongs to the technical field of power semiconductors, in particular to a silicon carbide diode with low turn-on voltage and low on-resistance. Background technique [0002] Silicon Carbide is one of the representatives of the third-generation wide-bandgap semiconductor materials. It has the characteristics of large forbidden band width, high critical breakdown electric field, high thermal conductivity and high saturation drift speed of electrons. , High-temperature and high-frequency power electronics have broad application prospects. [0003] Diodes are the earliest electronic devices used. With the innovation of electronic devices, PiN power diodes and Schottky power diodes are the most widely used in high-frequency and high-voltage applications. PiN diode has the advantages of high withstand voltage, low reverse leakage current, etc., but the built-in potential of PiN diode is relatively high, and the turn-on voltage is high; in addition, ...

AI Technical Summary

Problems solved by technology

PiN diodes have the advantages of high withstand voltage and low reverse leakage current, but the built-in potential of PiN diodes is relatively high, and the turn-on voltage is high; in addition, as a bipolar device, the conductance modulation effect produces a large number of minority loads in the drift region. The current greatly improves the conduction capability of the device and reduces the conduction loss; on the contrary, it also reduces the turn-off speed of the device, which limits the development of the diode to high frequency

Schottky diodes have a small forward turn-on voltage. As a unipolar device, there is no minority carrier storage effect, and the switching speed is fast, but the reverse leakage current is large, so it is difficult to apply to high-voltage and high-current fields.

[0004] In order to solve the problems of high turn-on voltage of traditional diodes and large leakage current of Schottky diodes, the present invention proposes a silicon carbide diode structure with three accumulation channels, low turn-on voltage and low on-resistance

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