MOS semiconductor devices having polysilicon gate electrodes and high dielectric constant gate dielectric layers and methods of manufacturing such devices

摘要

A semiconductor device includes a substrate divided into an NMOS region and a PMOS region, a first gate pattern formed on the PMOS region, and a second gate pattern formed on the NMOS region. The first gate pattern includes a first gate oxide layer pattern, a metal oxide layer pattern, a silicon nitride layer pattern and a first polysilicon layer pattern that are sequentially stacked. The second gate pattern includes a second oxide layer pattern and a second polysilicon layer pattern. Related methods are also provided.