Method of fabricating dual gate electrode of cmos semiconductor device

Abstract

In an embodiment, a method of fabricating a dual gate electrode includes forming an initial semiconductor layer doped with impurities of a first conductivity type on a semiconductor substrate having a first region and a second region. The initial semiconductor layer of the second region is partially etched to form a recessed semiconductor layer that is thinner than the initial semiconductor layer. Impurities of a second conductivity type different from the first conductivity type are implanted into the recessed semiconductor layer to define a first semiconductor layer in the first region and a second semiconductor layer in the second region, respectively. Then, the first and second semiconductor layers are annealed, and the annealed first semiconductor layer is planarized. The resulting structure may be etched to form gate electrodes that are capable of having high concentrations of impurities.