Low-input capacitance power semiconductor field effect transistor and self-alignment manufacture method thereof

Abstract

The invention relates to a low-input capacitance power semiconductor field effect transistor and a self-alignment manufacture method thereof and belongs to the semiconductor device technical field. The objective of the invention is to solve the problem of a Miller capacitance effect in an existing MOSFET device structure. A polysilicon gate of the semiconductor field effect device is disconnected at edges of two sides of a JFET region, so that polysilicon gates at two sides and a polysilicon field plate on the JFET region at the middle can be formed; an interval is formed between the polysilicon gates at two sides and the polysilicon field plate respectively; and the polysilicon field plate is connected with source region metal of the device at the edge of an active region of a chip, so that a capacitor between the DS of the device can be formed. The method includes the following steps that: a gate oxide layer is grown on an epitaxial layer, and a polysilicon layer is deposited on the gate oxide layer, and photo etching is performed, and therefore, polysilicon gates and a polysilicon field plate can be formed; an insulating layer is deposited; photo etching is performed on the insulating layer so as to expose the polysilicon gates at two sides; and injection and diffusion of a P well region and an N+ source region are performed, and photo etching is performed on contact holes of the gates and sources, and front-surface and back-surface metallization treatment is performed.

Description

technical field [0001] The invention relates to metal oxide semiconductor field effect transistors, especially power semiconductor devices such as power VDMOSFET, IGBT, planar (channel parallel chip surface) superstructure DMOS and IGBT, and in particular to low input capacitance power semiconductor field effect transistors and The self-alignment manufacturing method belongs to the technical field of semiconductor devices. Background technique [0002] Metal Oxide Semiconductor Field Effect Transistors (MOSFETs) are widely used as switching devices in fields such as power supplies. Such as figure 1 As shown, the basic principle of metal-oxide-semiconductor field-effect transistors is to form a semiconductor surface in NPN, on the P-type region and cover the PN junctions on both sides, and form an oxide layer metal (or silicon) gate structure on it, using the gate below The P-type region forms an inversion layer under the gate bias to connect the N-type regions on both side...

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Problems solved by technology

[0003] In order to solve the problem that the Miller capacitive effect occurs in the MOSFET device structure in the prior art, the switching speed of the device is reduced, the switching power loss is increased, and the circuit efficiency is reduced, the present invention provides a low input capacitance power semiconductor field effect transistor and its self-alignment method

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