A Vertical Double Diffused Metal Oxide Semiconductor Field Effect Transistor

Abstract

The invention discloses a vertical double diffused metallic oxide semiconductor field effect transistor. The vertical double diffused metallic oxide semiconductor field effect transistor comprises a substrate, a P well region, an N well region, gate oxide layers and grid electrodes, wherein the grid electrodes comprise a first grid electrode and a second grid electrode; the second grid electrode is positioned between the first grid electrode and the substrate; the thickness of the gate oxide layer between the first grid electrode and the second grid electrode is a first thickness; the thickness of the gate oxide layer between the second grid electrode and the substrate is a second thickness; and the second grid electrode is connected with a refresh structure through a switch so that the second grid electrode can be refreshed to an initial potential. The transistor provided by the invention solves the technical problem that a threshold voltage drift failure easily occurs due to the fact that a VDMOS in the prior art needs the gate oxide layers with relatively high thicknesses to meet voltage requirements but the relatively thick gate oxide layers can accelerate the drift of threshold voltage when the device is subjected to radiation. The technical effects of slowing down the threshold voltage drift and improving the reliability are reached.

Description

technical field [0001] The present invention relates to the field of semiconductors, in particular to a vertical double diffused metal oxide semiconductor field effect transistor (Vertical Diffuse Metal Oxide Semiconductor Field Effect Transistor, VDMOSFET). Background technique [0002] In the field of power semiconductors, such as figure 1 As shown, a vertical metal oxide semiconductor field effect transistor (Metal Oxide Semiconductor Field Effect Transistor, MOSFET) formed by a vertical double diffusion process is called a VDMOSFET, or VDMOS for short. Because this type of device usually needs to form a relatively large voltage between the gate G and the silicon substrate, the gate oxide thickness d is relatively thicker than that of a MOSFET device for logic applications. [0003] When a VDMOS device is used in space, it will be continuously exposed to ionizing radiation (such as X-rays and gamma rays, etc.), thereby resulting in a total dose effect (Total Ionizing Dos...

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Problems solved by technology

[0005] By providing a vertical double-diffused metal oxide semiconductor field effect transistor, the present invention solves the problem that VDMOS in the prior art requires a thicker gate oxide thickness to meet the voltage requirements, but a thicker gate oxide layer will accelerate the radiation of the device. The drift of the threshold voltage during the illumination causes the technical problem that the threshold voltage drift is prone to failure

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