Atomic local order of hafnium and silicon in Hf-based dielectric films

The aggressive scaling of complementary metal-oxide-semiconductor (CMOS) devices over the last decade has highlighted the limitations of SiO2 and nitrided SiO2 (SiON) as gate dielectrics in deep submicron devices. This technological dilemma has triggered a challenging search for a new material capable of replacing SiON as the gate dielectric in CMOS processing, with higher dielectric constant and most of the properties of SiO2. Among the many materials that have been investigated, Hf-based dielectrics have been extensively studied and are now considered for practical applications. Recently, it was found that nitrogen incorporation into the HfSiO network to for HfSiON promotes phase stability, improves the electrical performance, and reduces dopant diffusion. The bn==need remains, however, for a detailed atomic scale understanding of the fundamental issues concerning the atomistic origins of phase stability, as well as its evolution under thermal treatment, for both HfSiO and HfSiON dielectrics. (author)