Comparison of Chemical Vapor Deposited Hafnium Dioxide and Silicon Doped Hafnium Dioxide using either O_2, N_2O, H_2O, O_2 plasma, or N_2O plasma, and Hf (IV) t-butoxide

摘要

Hafnium oxide (HfO_2) and silicon containing hafnium oxide (HfSi_xO_y) thin films were deposited by thermal and plasma enhanced chemical vapor deposition (PECVD) using Hf (IV) t-butoxide and either O_2, N_2O, H_2O, O_2 plasma or N_2O plasma as an oxygen source. Silane, 2% in He, was added to the reactant gas mixture to incorporate Si. Deposition rate and composition dependence on substrate temperature was studied and the deposited films were annealed in air for 30 min at 1100℃ to observe changes in crystallinity and composition. Silicon incorporation was higher for H_2O deposited HfSi_xO_y films (5 at.%) than O_2 and N_2O deposited films (2 at.%) and had a lower deposition rate. Arrhenius plots reveal a non-simplistic reaction scheme since higher temperatures result in lower deposition rates due to precursor desorption. XRD indicate that as-deposited films using H_2O are amorphous while O_2 and N_2O deposited films are microcrystalline with a monoclinic phase.