The present disclosure relates to a method of forming a semiconductor structure, and particularly to a method of forming multiple gate dielectrics having different compositions, and structures formed by the same.
Gate dielectrics having different thicknesses are useful in providing a variety of field effect transistors on a same substrate. Replacement gate field effect transistors are compatible with high dielectric constant (high-k) gate dielectrics and metal gates. However, integration schemes that employ replacement gate field effect transistors tend to physically expose silicon-oxide-based dielectric material portions to damaging etch processes prior to deposition of a high-k gate dielectric material thereupon. In order to provide reliable semiconductor devices of various types, an integration scheme is desired that allows use of replacement gate structures with multiple types of gate dielectrics without damaging silicon-oxide-based dielectric material portions.