Novel trench gate IGBT (insulated gate bipolar transistor) provided with gate embedded diode and preparation method of novel trench gate IGBT

Abstract

The invention discloses a novel trench gate IGBT (insulated gate bipolar transistor) provided with a gate embedded diode and a preparation method of the novel trench gate IGBT. The preparation method comprises the following steps: firstly, performing P-base region and N type enhancement region implantation on an IGBT device main body; secondly, performing trench etching on the IGBT device main body and then depositing a gate oxide layer; thirdly, depositing an N type doped polysilicon layer on the grate oxide layer; fourthly, depositing a P type doped polysilicon layer on the N type doped polysilicon layer, and filling the trench with the P type doped polysilicon layer; fifthly, growing a polysilicon oxide layer on the P type doped polysilicon layer; sixthly, performing source electrode implantation on the IGBT device main body finishing the growth of the polysilicon oxide layer to form a source electrode region; seventhly, performing passivation layer depositing and etching on the IGBT device main body on which the source electrode region is formed to form a gate electrode and a cathode contact region. By arranging the embedded diode in a trench of the gate electrode, the resistance flowing out of a current channel from an anode via the gate electrode is increased, and the influence of a gate parasitic capacitor on the switching speed is inhibited.

Description

technical field [0001] The invention relates to the technical field of semiconductor device preparation, in particular to a novel trench gate IGBT with a gate embedded diode and a preparation method thereof. Background technique [0002] Trench gate IGBT enhances its cathode injection efficiency by increasing channel density, but at the same time increases its parasitic Miller capacitance. If the Miller capacitance is too large, it will reduce the switching speed of the IGBT and increase the switching loss of the IGBT. 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 characteristics and application range of the IGBT. [0003] In order to reduce the parasitic capacitance, K.OHI et al. proposed a structure, which reduces the parasitic capacitance on the side by using a capacitor isolated in series inside t...

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Problems solved by technology

Although this method can reduce the parasitic capacitance of the gate to a certain extent, not only the process method is relatively complicated, but also requires a complex polysilicon etching process, and it is easy to introduce contamination and defects during the process, increasing the gate leakage. electric current

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