Patent ID: 8324035

Claim:
A manufacturing method of silicon on insulator (SOI) metal oxide semiconductor (MOS) device eliminating floating body effects comprising steps of: (a) forming a shallow trench isolation structure on a Si material having the buried insulation layer to isolate an active region, and creating a gate region on the active region; (b) performing lightly source and drain region doping with high dose to form a lightly doped N-type source region with high doping concentration and a lightly doped N-type drain region with high doping concentration; wherein doping the lightly doped source and drain region at a dose of about 1e15/cm2, and the concentration of the lightly doped N-type source region and the lightly doped N-type drain region is set to about 1e19/cm3; (c) providing a spacer structure around the gate region, wherein the spacer structure covers a part of the surfaces of the lightly doped N-type source region and the lightly doped N-type drain region, and a mask with an opening thereon which is aligned with the edge of the spacer structure at a position of the lightly doped N-type source region is adopted to vertically heavily implant P ions underneath the lightly doped N-type source region to form a P-type region; (d) forming an N-type Si source region and an N-type drain region via once ion implantation and forming a body region between the N-type Si source region and the N-type drain region, and retaining some of the heavily doped P-type region between the N-type Si source region and the buried insulation layer as a heavily doped P-type region; and (e) forming a metal layer on a part of the surface of the N-type Si source region, then obtaining a silicide by the reaction of the metal layer with the Si material below during heat treatment, and contacting the silicide with the heavily doped P-type region in order to form an ohmic contact to release the holes accumulated in the body region of SOI MOS device and eliminate SOI MOS floating body effects; wherein the remaining Si material which does not react with the metal layer is treated as an N-type Si region, and an N-type source region is formed of the silicide obtained and the N-type Si region.