Precursor selection for metal–organic chemical vapor deposition of SrHfO₃ films with Sr(dpm)₂ and Sr(hfa)₂

Abstract

SrHfO₃ films were prepared using metal–organic chemical vapor deposition (MOCVD) with hafnium tetrakis(acetylacetonate) and two different Sr precursors, and the effects of Sr content in the vapor and deposition temperature on crystal phase and microstructure were investigated. With the strontium bis(dipivaloylmethanate) [Sr(dpm)₂] precursor, low Sr content of the deposited films regardless of Sr supply ratio resulted in no detectable SrHfO₃ formation. With the strontium bis(hexafluoroacetylacetonate) [Sr(hfa)₂] precursor, along with linear increase of Sr content in the deposited films, the primary crystal phase of the film changed from monoclinic HfO₂ to orthorhombic SrHfO₃ to SrCO₃. A single-phase orthorhombic SrHfO₃ film was prepared with the Sr(hfa)₂ precursor at 1373 K and 42 mol %Sr (corresponding to 50 mol %Sr in the film).