THE USE OF DISPOSABLE DOUBLE SPACER AND SELF-ALIGNED COBALT SILICIDE FOR LDD MOSFET FABRICATION

A novel type of LDD MOSFET with an optional self-aligned silicide metallization is presented. A disposable double spacer of silicon nitride/amorphous silicon is used to enable LDD MOSFET's to be fabricated with just two masking steps compared to four in the conventional oxide spacer LDD FET. The alpha-Si spacer is disposed after is has been used to pattern the nitride. The nitride acts as a second spacer to block low-energy S/D implants and to shift LDD implants away from the gate edge. Self-aligned metallization can be realized using the nitride as silidication barrier.