Production and characterization of HfO2 high-k dielectric layers by sputtering technique

Abstract

HfO2 thin films have been deposited on Si by in-situ spectroscopic ellipsometric sputtering technique. The grown films have been examined by various diagnostic and analysis techniques (Spectroscopic Ellipsometer (SE), FTIR, XRD, XPS). The optimization of in-situ SE sputtering system has been processed according to the measurement results of the grown HfO2 films. From the measurements simultaneously taken by using SE, film thickness, refractive index and real part of dielectric function have been examined as a function of deposition time. It was found that the thickness changes linearly with deposition time. The formation of undesired SiO2 interfacial layer has been tried to be prevented and searched by using FTIR. MOS capacitors from the oxides having best qualities have been produced to obtain electrical properties of grown oxides. The process of production-characterization and development of oxidation conditions have been achieved and the following results have been obtained: (a) Low O2/Ar gas ratio and 30-40 watt power have been considered as the most convenient oxidation parameters. (b) The formation of SiO2 interface has not been prevented but formation of HfxSiOy has been obtained. (c) The refractive index value (n.2.1) of bulk HfO2 at 632 nm has been obtained.