Importance

Loading Importance Indicators...

Abstract

A method of forming an insulated-gate field-effect transistor, and the transistor formed thereby, is described. According to a first embodiment, an inverted-T gate structure is formed by the deposition of a polycrystalline silicon layer, followed by the deposition of a metal silicide layer thereover. The metal silicide layer is etched with etchant which does not significantly etch polysilicon, to define the upper portion of the gate electrode. The reachthrough lightly-doped source/drain extensions are then implanted through the polysilicon layer, using the upper gate electrode portion as a mask. Sidewall spacers are formed on the sides of the upper portion of the gate electrode, and the polysilicon etched using the spacers as a mask, to define the inverted-T gate structure. In addition, either with the inverted-T gate structure or in conjunction with conventional gate structures, a method is disclosed which uses a first sidewall film to define the location of the source/drain implant relative to the LDD regions, and a second sidewall spacer to space direct react silicide formation from the gate, so that the dimensions of the graded junction may be defined independently from that of the silicidation reaction.

Loading the Abstract Image...

First Claim