Raised silicide source/drain mos transistors having enlarged source/drain contact regions and method

Abstract

A method is provided for forming silicided source/drain electrodes in active devices in which the electrodes have very thin junction regions. In the process, adjacent active areas are separated by isolation regions, typically by LOCOS isolation, trench isolation or SOI/SIMOX isolation. A contact material, preferably silicide, is deposited over the wafer and the underling structures, including gate and interconnect electrodes. The silicide is then planed away using CMP, or another suitable planing process, to a height approximate the height of the highest structure. The silicide is then electrically isolated from the electrodes, using an etch back process, or other suitable process, to lower the silicide to a height below the height of the gate or interconnect electrode. The wafer is then patterned and etched to remove unwanted silicide. The remaining silicide typically forms silicided source regions and silicided drain regions that extend over a portion of the adjacent isolation regions such that the silicided source/drain regions are larger than the underlying source/drain regions to provide a larger contact area.