Chemical interaction and ligand exchange between a [(CH3)(3)Si](3)Sb precursor and atomic layer deposited Sb2Te3 films

摘要

The chemical interaction between the [(CH3)(3)Si](3)Sb precursor and atomic layer deposited Sb2Te3 thin films was examined at temperatures ranging from 70 to 220 degrees C. The trimethylsilyl group [(CH3)(3)Si] displays greater affinity for Te than for Sb, and this drives replacement of Te in the film with Sb from the [(CH3)(3)Si](3)Sb precursor, while eliminating volatile [(CH3)(3)Si](2)Te, especially at elevated temperatures. The compositions of the resulting Sb-Te layers lie on the Sb2Te3-Sb tie line. The incorporation behavior of [(CH3)(3)Si](3)Sb was explained in terms of a Lewis acid-base reaction. The exchange reactions occurred to relieve the unfavorable hard-soft Lewis acid-base pair between the trimethylsilyl group and Sb in [(CH3)(3)Si](3)Sb. Such a reaction could be usefully adopted to control the chemical composition of ternary Ge-Sb-Te thin films.