Method of forming carbon-containing silicon nitride layer

A method for forming a gate, comprising:

• providing a substrate having a gate dielectric layer thereon;
• forming a conductive layer on the gate dielectric layer;
• patterning the conductive layer and the gate dielectric layer to form a gate electrode;
• forming offset spacers on the sidewalls of the gate electrode, the material of the offset spacers is carbon-containing silicon nitride;
• forming a material layer over the substrate and covering the gate electrode, wherein the material layer comprises a carbon-containing silicon nitride layer formed by low pressure chemical vapor deposition (LPCVD);
• and
• etching back the material layer to form spacers over sidewalls of the gate electrode.