Manufacture method for transverse symmetrical DMOS (double diffusion metal-oxide-semiconductor) pipe

Abstract

Disclosed are a transverse symmetrical DMOS (double diffusion metal-oxide-semiconductor) pipe and a manufacture method thereof. The transverse symmetrical DMOS pipe comprises an epitaxial layer of a first doping type, and two active regions of a second doping type, which are located on the epitaxial layer, wherein active region metal electrodes contacted with the active regions in Ohm contact mode are arranged above the active regions, a drifting region of the second doping type is arranged between the two active regions, a channel region of the first doping type is arranged in the middle of the drifting region, an insulating layer is arranged above the drifting region and the channel region in covering mode, grid electrodes and ancillary gratings are distributed on the insulating layer and respectively located above the channel region and the drifting region, and the ancillary gratings are provided with lead connection holes. The invention further discloses a manufacture method of the transverse symmetrical DMOS pipe. According to the transverse symmetrical DMOS pipe and the manufacture method thereof, conduction resistance of the DMOS pipe is reduced by applying positive voltage on the ancillary gratings and then attracting electric charges so as to invert the electric charges below the ancillary gratings, the ancillary gratings and the grid electrodes are connected so as to increase gating drain capacitance when the transverse symmetrical DMOS pipe is used as an electrostatic protection device, gate charge coupling speed is improved, and quick starting of the electrostatic protection device is facilitated.

Description

technical field [0001] The invention belongs to the field of semiconductor manufacturing and relates to the design and manufacture of high-voltage DMOS tubes, in particular to a method for manufacturing a laterally symmetrical DMOS tube. Background technique [0002] DMOS is the abbreviation of double-diffused MOSFET (double-diffused MOSFET). Since DMOS uses a shallow implanted drift region to withstand high voltage, the withstand voltage performance between the source and drain of DMOS is greatly improved; there are two main types of DMOS, vertical double-diffused metal Oxide semiconductor field effect transistor VDMOSFET (vertical double-diffused MOSFET) and lateral double-diffused metal oxide semiconductor field effect transistor LDMOSFET (lateral double-dif fused MOSFET). [0003] DMOS device on-resistance refers to the resistance from drain to source when the device is working. For LDMOS devices, the on-resistance should be reduced as much as possible. When the on-res...

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Problems solved by technology

[0005] For DMOS in the high-voltage process, due to the need to adopt the design of the drift region to increase the withstand voltage between the source and the drain, the distance between the polysilicon lead of the gate and the drain is increased, and the capacitance value of the parasitic capacitance CGD is very small. During the above-mentioned electrostatic protection process , the drain ESD voltage is difficult to couple to the gate, and the electrostatic protection effect becomes worse

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