SURFACE ANALYSIS OF AMORPHOUS Ta-Cu ALLOY THIN FILMS.

In the present investigation, amorphous thin (approximately 3000 Angstrom thick) Ta-Cu alloy films, with varying composition, were deposited on GaAs substrates by co-sputtering of high purity (99. 999%) Ta and Cu targets. A Au layer was subsequently deposited on each Ta-Cu sample. Annealing temperatures as high as 800 degree C were used. The AES data, combined with the elemental sensitivity factors, provided information on the nominal stoichiometry of the alloy film. Inter-diffusion involving the amorphous layer, the Au and GaAs were studied by AES. ESCA analysis provided additional information on the chemical bonding states of the constituent elements. The Ta//9//3Cu//7 film prevented the intermixing of Au, Ga and As for annealing up to 700 degree C. Out-diffusion of Ga and As through the Ta//9//3Cu// 7 layer was detected after an 800 degree C anneal.