Plasma enhanced atomic layer deposition of Fe2O3 thin films

Abstract

Atomic layer deposition of Fe₂O₃ is generally performed at temperatures above 350 °C. In this work, Fe₂O₃ thin films were deposited by remote plasma enhanced atomic layer deposition using tertiary butyl ferrocene (TBF) and O₂ plasma in a broad temperature range starting from 150 to 400 °C. A maximum growth rate of 1.2 Å per cycle was achieved between 300 and 350 °C. Below 300 °C, the saturated growth per cycle was found to depend on the temperature of the sample. All the deposited films were pure with no significant amount of carbon contamination. Films deposited at 250 °C and above were crystalline with an α-Fe₂O₃ crystal structure, while the low temperature films were crystallized by a post-deposition annealing in He. Annealing in H₂ induced the formation of metallic iron.