Solution-processed HfGdO gate dielectric thin films for CMOS application: Effect of annealing temperature

Annealing temperature dependent microstructure, optical and electrical properties of sol-gel-deposited HfGdO high-k gate dielectric thin films on Si substrates are systematically investigated. X-ray spectroscopy (XPS) analyses have confirmed that the interfacial layer at HfGdO/Si interface is mainly silicate and the component increases with increasing the annealing temperature. Moreover, the band offsets for HfGdO/Si gate stack as a function of annealing temperature also have been determined. As a result, it can be noted that increase in valence band offset (Delta E-v) and reduction in conduction band offset (Delta E-c) have been detected. Electrical characterizations have indicated that higher annealing temperature effectively improves the electrical characteristics, such as the increased effective permittivity (k) and the decreased flat band voltage shift (Delta V-fb). However, due to the reduced DEc and the appearance of crystallization, increased leakage current density has been observed with the increase in annealing temperature. (C) 2017 Elsevier B.V. All rights reserved.