Evolution of the Al_2O_3/Ge(100) interface for reactively sputter-deposited films submitted to postdeposition anneals

摘要

Al_2O_3 was deposited by pulsed DC reactive sputter on Ge(l 0 0) aiming at producing layers with reduced OH and H_2O content in comparison with water-based atomic layer deposition. In this way, the intrinsic interaction of Al_2O_3 with Ge could be probed. Photoelectron spectroscopy showed evidence of a GeO_2 interlayer in as-deposited samples. Thermal annealing in Ar or forming gas for 30 min at 350 ℃ reduced the amount of oxidized Ge, I.e. significant activity took place at the Al_2O_3/Ge interface irrespective of annealing ambient. The remaining transition layer consisted essentially of aluminum germanates. Analysis of Si companion samples indicates that in the absence of an oxidizing agent, Al_2O_3/Ge is more stable than AbCh/Si.