The oxidation kinetics of thin copper films studied by resistivity measurements

Resistivity measurements on thin metal films allow to study the kinetics of oxidation. The method is applied to 50 - 60 nm thick copper films deposite d on glass substrates under UHV conditions. After annealing at 150 degrees C, the films are exposed to pure oxygen at various temperatures in the rang e 85 - 135 degrees C, and the electrical resistivity is recorded in situ. A t these temperatures, the oxygen begins to penetrate into the interior of t he films, which results in a relatively steep increase in the film resistiv ity. A linear time law is valid to good approximation, which can be attribu ted to the influence of the dissociation of an adsorbed molecular species o f oxygen on the reaction velocity. A potential diffusion of oxygen in the g rain boundaries is also discussed.