METHOD OF MANUFACTURING MOS TRANSISTOR WITH FLUORIDE IMPLANTATION ON SILICON NITRIDE ETCHING STOP LAYER

摘要

A method of manufacturing a MOS transistor. A substrate having a gate oxide layer, a gate electrode and spacers attached to the sidewalls of the gate electrode is provided. A source/drain (S/D) implantation is conducted to form a source/drain region in the substrate on each side of the gate electrode. A self-aligned silicide (Salicide) process is carried out to form a self-aligned silicide layer over the exposed gate electrode and source/drain region. A silicon nitride layer serving as an etching stop is formed over the substrate. A fluoride blanket implantation of the silicon nitride etching stop layer is carried out using an implantation dosage of about 5x1013~5x1014 cm2 and at an implantation energy level between 2 KeV~5 KeV. The fluorides implanted into the silicon nitride layer capture hydrogen within the silicon nitride layer, thereby reducing free hydrogen concentration and increasing threshold voltage stability of the MOS transistor.