Thermal stability and electrical characteristics of ultrathin hafnium oxide gate dielectric reoxidized with rapid thermal annealing

Abstract

Dielectric properties of ultrathin hafnium oxide reoxidized with rapid thermal annealing (RTA) have been investigated. Capacitance equivalent oxide thickness (CET) of 45 Å hafnium oxide was scaled down to ∼10 Å with a leakage current less than 3×10−2 A/cm2 at −1.5 V (i.e., ∼2 V below VFB). Leakage current increase due to crystallization was not observed even after 900 °C rapid thermal annealing (RTA), but CET did increase after high temperature RTA due to the interfacial layer growth and possible silicate formation in the HfO2 film.