Process for manufacturing surface channel PMOS device with polycide

Abstract

The invention discloses a process for manufacturing a surface channel PMOS device with polycide, which comprises the following steps of: 1, doping an N-type impurity on a P-type silicon substrate to form an N-type channel; 2, depositing a layer of oxidized silicon nitride on the surface of a silicon wafer; 3, depositing a layer of polysilicon on the surface of the silicon wafer and doping a P-type impurity in a gate region of the layer of polysilicon to form P-type polysilicon; 4, forming the polycide on the surface of the silicon wafer; 5, etching the polycide, the P-type polysilicon and the oxidized silicon nitride except for the polycide, the P-type polysilicon and the oxidized silicon nitride outside the gate region until the N-type channel is exposed; 6, depositing a layer of silicon nitride on the surface of the silicon wafer and etching the layer of silicon nitride until the N-type channel is exposed and part of silicon nitride side wall is reserved on the side wall of the P-type polysilicon; and 7, performing ion implantation of the P-type impurity on the silicon wafer to form a source region and a drain region of the PMOS device. The surface channel PMOS device manufactured by the invention can realize low leakage of electricity under a lower threshold voltage.

Description

technical field [0001] The invention relates to a manufacturing process of a semiconductor device, in particular to a manufacturing process of a PMOS device. Background technique [0002] In semiconductor integrated circuits with a size of 0.35 μm and above, polysilicon gates of MOS devices are usually covered with polycide. Polysilicon is formed by the reaction of refractory metals and polysilicon. Refractory metals include cobalt, molybdenum, platinum, tantalum, titanium, tungsten, etc. During the formation of the polysilicon, the silicon oxide remaining on the silicon surface will be reduced, thereby reducing the contact resistance of the polysilicon gate. [0003] The polysilicon compound covers the polysilicon gate, and its dense characteristics make it impossible for ions to be implanted into the polysilicon gate during the source-drain implantation of the MOS device. In this way, the doping of the polysilicon gate can only be done in-situ when the polysilicon is dep...

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Problems solved by technology

The biggest disadvantage of buried channel devices is that they must have a higher threshold voltage to have a lower leakage current

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