Patent ID: 8178446

Claim:
A method of depositing a strained metal nitride film in a metal gate stack of a field effect transistor (FET) device in a process chamber, comprising: exposing a substrate, having an exposed gate stack region of the FET device to a gas comprising a metal precursor; exposing the substrate to a gas comprising a first nitrogen precursor configured to react with the metal precursor with a first reactivity characteristic; and exposing the substrate to a gas comprising a second nitrogen precursor configured to react with the metal precursor with a second reactivity characteristic different than the first reactivity characteristic such that a property of the metal nitride film formed in the gate stack region of the FET device changes during the exposing the substrate to a gas comprising a second nitrogen precursor to provide a strain within a channel region of the FET device during deposition the strained metal nitride film such that carrier mobility within the channel region is improved.