Effects of rapid thermal annealing on interfacial and electrical properties of Gd-doped HfO2 high-k gate dielectrics

Abstract

In this work, we systematically investigated the effects of rapid thermal annealing on the interfacial and electrical properties, as well as band offsets of sputtering-derived Gd-doped HfO2 film on Si substrate. The results indicate that annealing temperature has little effect on the interfacial properties of Gd-doped HfO2 thin films, and the main component of interfacial layer is silicate without any silicide. Moreover, heat treatment can effectively improve the C–V characteristics of the samples, such as the increase of effective permittivity, reduction in ΔVfb and no obvious frequency dispersion. However, the increase of annealing temperature leads to the increase of leakage current density of Al/Gd-doped HfO2/Si MOS capacitor due to the decrease of the conduction band offset (ΔEc) and further crystallization of the samples. These investigation results might provide the guidance for the performance optimization of high k gated dielectrics to meet the requirements of future complementary-metal-oxide-semiconductor (CMOS) devices.