COMPLETELY PASSIVATED HIGH-CONDUCTIVITY COPPER-FILMS MADE BY ANNEALING CU AL BILAYERS/

Thin films made by annealing Cu(500 nm)/Al(7 nm)/SiO2/Si are investiga ted using Rutherford backscattering and resistivity measurements. Anne aling these films in a low pressure of oxygen results in the formation of a thin surface layer of hole-free aluminum oxide which protects th e underlying copper from oxidation. Even when heated in air at 350 deg rees C for 4 h, no growth of copper oxide is detected. These films hav e a resistivity as low as 2.4 mu Omega cm, comparable to the resistivi ty of pure copper films (2.1 mu Omega cm) made in the same deposition system. The use of such films for microelectronic metallization is bri efly discussed. (C) 1996 American Institute of Physics.