US Patent 7790635 Method to increase the compressive stress of PECVD dielectric films

A method for forming a compressive stress carbon-doped silicon nitride layer is provided. The method includes forming an initiation layer and a bulk layer thereon, wherein the bulk layer has a compressive stress of between about −0.1 GPa and about −10 GPa. The initiation layer is deposited from a gas mixture that includes a silicon and carbon-containing precursor and optionally a nitrogen and/or source but does not include hydrogen gas. The bulk layer is deposited from a gas mixture that includes a silicon and carbon-containing precursor, a nitrogen source, and hydrogen gas. The initiation layer is a thin layer that allows good transfer of the compressive stress of the bulk layer therethrough to an underlying layer, such as a channel of a transistor.