Method of forming a mos device with an additional layer

Abstract

A method of forming MOS devices is provided. The method includes providing a semiconductor substrate, forming a gate dielectric over the semiconductor substrate, forming a gate electrode over the gate dielectric, forming a source/drain region in the semiconductor substrate, forming an additional layer, preferably by epitaxial growth, on the source/drain region, and siliciding at least a top portion of the additional layer. The additional layer compensates for at least a portion of the semiconductor material lost during manufacturing processes and increases the distance between the source/drain silicide and the substrate. As a result, the leakage current is reduced. A transistor formed using the preferred embodiment preferably includes a silicide over the gate electrode wherein the silicide extends beyond a sidewall boundary of the gate electrode.