US Patent 9324841 Methods for preventing oxidation damage during FinFET fabrication

Embodiments of the present invention provide improved methods for fabricating field effect transistors such as finFETs. Stressor regions are used to increase carrier mobility. However, subsequent processes such as deposition of flowable oxide and annealing can damage the stressor regions, diminishing the amount of stress that is induced. Embodiments of the present invention provide a protective layer of silicon or silicon oxide over the stressor regions prior to the flowable oxide deposition and anneal.