Method of manufacturing depletion type double-diffused metal oxide semiconductor

Abstract

The invention provides a method of manufacturing a depletion type double-diffused metal oxide semiconductor (DMOS), comprising: employing a polycrystalline silicon photomask to inject P type doping elements into an N-EPI after generating the N-EPI on an N-sub so as to form P type body regions; injecting N type doping elements into the N-EPI to from N type channels on the surfaces of the P type body regions; growing gate oxide on the N-EPI provided with the N type channels, and growing a polycrystalline silicon layer on the gate oxide; performing photoetching and etching on the polycrystalline silicon layer to form a polycrystalline silicon window and to expose to the N type channels; and injecting doping elements into the N type channels through the polycrystalline silicon window to form source areas. According to the invention, the method employs the polycrystalline silicon photomask twice and utilizes the enhanced DMOS production process to generate a depletion type DMOS; the production process is completely compatible with a present DMOS production process, and is relatively simple.

Description

technical field [0001] The invention relates to the field of semiconductor devices and their manufacturing techniques, in particular to a method for manufacturing a depletion-type double-diffused metal oxide transistor. Background technique [0002] Among the currently used DMOS transistors (Double-diffused Metal Oxide Semiconductor, double-diffused metal oxide semiconductor transistors), the common types can be divided into two types: enhancement type and depletion type, and the structure of the N-channel enhancement type DMOS cell is as follows figure 1 As shown, the structure of the N-channel depletion DMOS cell is as figure 2 shown. Taking the N-channel MOS transistor as an example, the enhanced MOS transistor does not have a conductive channel at zero gate bias voltage, and cannot conduct electricity. The channel is normally closed and can only be formed when the gate bias voltage is positive (greater than the turn-on voltage). The channel is conductive; while the de...

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Problems solved by technology

but from figure 1 and figure 2 It can be seen from the figure that there are differences in the cellular structure of the enhanced type and the depleted type, so the production process will also be different. Two sets of production lines require two sets of production equipment, and the production cost is relatively high.

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