Thyristor and its manufacturing method

Abstract

The present invention provides a thyristor comprising a substrate of the first conductivity type, a buried layer of the second conductivity type formed on the substrate, an epitaxial layer of the second conductivity type formed on the upper surface of the buried layer, and an epitaxial layer of the second conductivity type formed on the epitaxial layer A first implantation region of the first conductivity type on the upper surface, a second implantation region of the second conductivity type located in the first implantation region, extending from the lower surface of the substrate to a plurality of first conductivity type implants in the substrate at intervals The third implantation region, the oxide layer located at the junction between the first implantation region and the second implantation region, extends from the upper surface of the first implantation region to the first implantation region to open a trench located outside the oxide layer, The trench is filled with a polysilicon layer of the first conductivity type, a gate metal layer located on the first injection region and the upper surface of the polysilicon layer. The invention also provides a preparation method of the thyristor, which reduces the forward voltage drop and conduction loss of the thyristor, and improves the working efficiency and reliability of the thyristor.

Description

technical field [0001] The invention relates to the field of design and manufacture of semiconductor devices, in particular to a thyristor and a preparation method thereof. Background technique [0002] The thyristor is a three-terminal controllable switching device including PNPN four or more semiconductor layers. Its three terminals are the anode, cathode and gate respectively. By controlling the gate, the thyristor can be changed from the cut-off state to the conduction state. It can also change from the on state to the off state. It can control a large current with a small current, so that semiconductor devices can be extended from weak current to strong current. Therefore, thyristors are widely used in electronic circuits such as controllable rectification, AC voltage regulation, non-contact electronic switches, inverters and frequency conversion, and are typical devices for controlling large currents with small currents. [0003] With the development of power electro...

AI Technical Summary

Problems solved by technology

[0003] With the development of power electronics technology, the technical indicators of thyristors include: forward voltage drop, reverse breakdown voltage and turn-off loss. At present, thyristors with traditional structures and processes often only have high reverse breakdown voltage. However, when the shutdown time is long, the loss in the shutdown process is large, which leads to an increase in the power consumption of the entire circuit system, and even cannot work normally at high frequencies.

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