Characterization of hafnium silicate thin films grown by MOCVD using a new combination of precursors

Abstract

Hafnium silicate [(HfO2)X(SiO2)1−X] films were deposited by metalorganic chemical vapor deposition using a new combination of precursors: tetrakis-diethylamido-hafnium [Hf(NEt2)4] and tetra-n-butyl-orthosilicate [Si(OnBu)4]. An atomically flat interface of silicate/silicon was observed with no interfacial silicon oxide layers. The impurity concentrations in grown films were less than 0.1at% (below detection limits). Hafnium silicate films were amorphous up to 800°C. Above 900°C, phase separation of the films occurred into crystalline HfO2 and amorphous Si-rich silicate phases. Dielectric constant (k) of the Hf-silicate films was about 8. Hysteresis in capacitance–voltage (C–V) measurements was less than 0.1V.