Nitrogen-rich silicon nitride sidewall spacer deposition

A method of manufacturing semiconductor devices, the method comprising the steps of:

• forming a silicon gate electrode, having an upper surface and side surfaces, overlying a silicon substrate with a gate dielectric layer therebetween, a spacer oxide liner disposed on the side surfaces and on source/drain regions in the substrate:
• depositing a silicon nitride layer at:
• a SiH4 flow rate of about 200 sccm to about 450 sccm;
• a N2 flow rate of about 4,000 sccm to about 5,000 sccm,
• a NH3 flow rate of about 4,000 sccm to about 5,000 sccm;
• a high frequency RF power of about 400 watts to about 700 watts;
• a low frequency RF power of about 100 watts to about 200 watts;
• a pressure of about 1.6 torr to about 2.2 torr;
• and a temperature maintained at about 400° C. to about 420° C.;
• anisotropically etching the silicon nitride layer to form silicon nitride sidewall spacers on the spacer oxide liner;
• depositing a refractory metal layer;
• heating to react the refractory metal with underlying Si to form a metal silicide layer on the gate electrode and a metal silicide layer on the source/drain regions;
• and
• removing unreacted refractory metal from the silicon nitride sidewall spacers.