Trench gate IGBT (Insulated Gate Bipolar Transistor) with gate embedded diode and preparation method thereof

Abstract

The invention discloses a preparation method of a trench gate IGBT (Insulated Gate Bipolar Transistor) with a gate embedded diode, which comprises: S1, carrying out P-base region and N-type enhancement region injection on an IGBT device main body; S2, carrying out trench etching on the IGBT device main body and depositing a gate oxide layer; S3, carrying out N-type doped polysilicon layer deposition on a trench of the IGBT device main body and full filling the trench; S4, etching out redundant N-type doped polysilicon outside the trench of the IGBT device main body; S5, carrying out deposition of a polycrystalline silicon oxide layer on the surface of the IGBT device main body; S6, carrying out source injection on the IGBT device main body of which deposition of polycrystalline silicon oxide layer is completed so as to form a source region; S7, carrying out P-type doping on the trench of the IGBT device main body, and forming a P-typed doped polycrystalline silicon region at the top of a trench gate. By forming the embedded diode in the trench of a gate electrode, a resistance flowing out of a current channel from an anode through the gate is increased, and influence of a gate stray capacitance on a switching speed is restrained.

Description

technical field [0001] The invention relates to the technical field of semiconductor device preparation, in particular to a trench gate IGBT with a gate embedded diode and a preparation method thereof. Background technique [0002] In IGBT devices, a trade-off between on-state voltage and off-time is achieved by using a new etching process implemented by silicon dry etching technology borrowed from the large-scale integration (LSI) process. Trench gate IGBT enhances its cathode injection efficiency by increasing channel density, but at the same time increases its parasitic Miller capacitance. If the parasitic Miller capacitance of the device is too large, the switching speed of the IGBT will be reduced and the switching loss of the IGBT will be increased. At the same time, due to the large square resistance of the polysilicon gate, the ability of the external series gate resistor to control the di / dt and dv / dt of the IGBT switch is reduced, thereby weakening the electrical ...

AI Technical Summary

Problems solved by technology

Although this method can reduce the parasitic capacitance of the gate to a certain extent, its disadvantage is that the process method is relatively complicated, and a complex polysilicon etching process is required. At the same time, it is easy to introduce contamination and defects during the process, which increases the leakage current

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