Electrical characteristics of MOS capacitor with HfTiON gate dielectric and HfTiSiON interlayer

The paper reports that HfTiO dielectric is deposited by reactive co-sputtering of Hf and Ti targets in an Ar/O₂ ambience, followed by an annealing in different gas ambiences of N₂, NO and NH₃ at 600℃ for 2 min. Capacitance--voltage and gate-leakage properties are characterized and compared. The results indicate that the NO-annealed sample exhibits the lowest interface-state and dielectric-charge densities and best device reliability. This is attributed to the fact that nitridation can create strong Si \equiv N bonds to passivate dangling Si bonds and replace strained Si--O bonds, thus the sample forms a hardened dielectric/Si interface with high reliability.