USE OF SILICON GERMANIUM AND OTHER ALLOYS AS THE REPLACEMENT GATE FOR THE FABRICATION OF MOSFET

摘要

PURPOSE: Use of silicon germanium and other alloys as the replacement gate for the fabrication of MOSFET is provided to manufacturing a MOSFET device wherein the source region and the drain region are formed before formation of the gate and allows the use of any type of gate dielectric material. CONSTITUTION: A method for fabricating a MOSFET structure on a substrate comprises the steps of: forming an island above a gate region in the substrate, island being formed of Si.sub.1-x Ge.sub.x, wherein x is in the range of about 0.05 to about 1.0; building a sidewall about island; forming a source region and a drain regions in the substrate; selectively removing the island without removing the sidewall, thereby leaving a void over the gate region; and filling the void with a gate structure.