P-channel depletion MOS (metal oxide semiconductor) transistor and preparation method thereof

Abstract

The invention discloses a P-channel depletion MOS (metal oxide semiconductor) transistor and a preparation method thereof. The method comprises the following steps: preparing a field oxide layer on the upper surface outside an area of an MOS electrode to be prepared of an N-type substrate, and preparing a gate oxide layer on an area which is not covered by the field oxide layer; preparing an undoped polysilicon layer on an area of an MOS gate to be prepared on the gate oxide layer; injecting boron ions of the set dosage into the area which is not covered by the field oxide layer above the N-type substrate so that the undoped polysilicon layer forms a P-type polysilicon layer and the surface layer on the N-type substrate which is not covered by the undoped polysilicon layer and the field oxide layer forms a P-type source (drain) area; and performing annealing treatment on the N-type substrate after the source (drain) area and the P-type polysilicon layer are formed so as to obtain the P-channel depletion MOS transistor. The method simplifies the preparation process and increases the start voltage of the transistor.

Description

technical field [0001] The invention relates to the technical field of semiconductors, in particular to a P-channel depletion MOS (Metal-Oxide-Semiconductor, Metal-Oxide-Semiconductor) transistor and a preparation method thereof. Background technique [0002] The turn-on voltage of the P-channel enhancement MOS transistor is less than 0, and the transistor is turned on only when the voltage value is less than the turn-on voltage. Therefore, when the difference between the gate and source voltage of the P-channel enhancement MOS transistor (referred to as "gate-source When the voltage ") is 0, the MOS tube cannot be turned on; the turn-on voltage of the P-channel depletion MOS transistor is greater than 0, therefore, when the gate-source voltage is 0, the MOS tube can be turned on, that is, between the source and the drain conduction between. [0003] In the traditional P-channel depletion-mode MOS transistor manufacturing process, a P-type conductive channel is generally fa...

AI Technical Summary

Problems solved by technology

Its production process is complex, requiring multiple photolithography and ion implantation (the whole process includes four photolithography and two ion implantation), resulting in waste of resources and increased production costs

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