关键词: HfSiON, high-k gate dielectric, sputtering, leakage current

Abstract: This paper presents a method using simple physical vapour deposition to form high-quality hafnium silicon oxynitride (HfSiON) on ultrathin SiO$_{2}$ buffer layer. The gate dielectric with 10 Å (1 Å = 0.1 nm) equivalent oxide thickness is obtained. The experimental results indicate that the prepared HfSiON gate dielectric exhibits good physical and electrical characteristics, including very good thermal stability up to 1000${^\circ}$C, excellent interface properties, high dielectric constant ($k=14$) and low gate-leakage current ($I_{\rm g}=1.9\times 10^{ - 3}$ A/cm$^{2} @V_{\rm g}=V_{\rm fb}-1$ V for EOT of 10 {\AA}). TaN metal gate electrode is integrated with the HfSiON gate dielectric.The effective work function of TaN on HfSiON is 4.3 eV, meeting the requirements of NMOS for the metal gate. And, the impacts of sputtering ambient and annealing temperature on the electrical properties of HfSiON gate dielectric are investigated.

Key words: HfSiON, high-k gate dielectric, sputtering, leakage current