Strip cell structure of a vdmos device and manufacturing method thereof

Abstract

Disclosed are a strip-shaped cellular structure of a VDMOS device and a manufacturing method therefor. The strip-shaped cellular structure comprises: a drain region; an epitaxial layer located on the drain region; a lateral channel, a first well region and a second well region which are located in the epitaxial layer, and a first source region embedded in the first well region and a second source region embedded in the second well region, wherein the lateral channel comprises a channel well region and a channel source region embedded in the channel well region; a gate oxide layer located on the epitaxial layer, with the gate oxide layer completely covering the lateral channel; and a polycrystalline silicon layer located on the gate oxide layer, the direction of a long side of the polycrystalline silicon layer being perpendicular to that of the lateral channel. In the present invention, by adding a lateral channel which is perpendicular to the direction of a long side of a polycrystalline silicon layer in an epitaxial layer below the polycrystalline silicon layer, the channel width and area of a cellular structure are increased, which can effectively reduce the conduction resistance and improve the current conduction capability.

Description

technical field [0001] The invention relates to the technical field of semiconductors, in particular to the technical field of power semiconductor devices, in particular to a strip-shaped cell structure of a VDMOS device and a manufacturing method thereof. Background technique [0002] VDMOS (Vertical Double-diffused Metal Oxide Semiconductor) device is a power semiconductor device that has the advantages of both bipolar transistors and ordinary MOS devices. Compared with bipolar transistors, it has fast switching speed, small switching loss, high input impedance, low driving power, good frequency characteristics, high transconductance linearity, no secondary breakdown problem of bipolar power devices, and safe The work area is large. Therefore, VDMOS devices are ideal power semiconductor devices for both switching and linear applications. [0003] For VDMOS devices, one of its important indicators is the on-resistance. With the development of VDMOS devices, their structu...

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Problems solved by technology

Therefore, if figure 1 As shown, in the strip cell structure of the prior art VDMOS device, the N- epitaxial layer 102 at the position below the polysilicon layer 105 is not fully utilized, thereby not effectively increasing the width and area of ​​the channel, so that the strip The on-resistance of the cell structure is relatively large, and the current conduction capability is limited

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