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((OBu)-Bu-n)(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 0.1 at% (below detection limits). Hafnium silicate films were amorphous up to 800degreesC. Above 900degreesC, 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 0.1 V. (C) 2003 Elsevier B.V. All rights reserved.