Oblique angle deposition of Au/Ti porous getter films.

Interdiffusion in gold/titanium films with titanium evaporated on silicon at different oblique angles (0°, 30°, 50°, and 70°) and gold evaporated under normal incidence is investigated using a scanning electron microscope and in-situ sheet resistance measurements for the optimization of the films' effective gettering ability during and after a low-temperature thermal activation. Films have a tilted columnar structure and a porosity increasing with the deposition angle in agreement with calculated values. The oxygen effective gettering ability, characterized by energy-dispersive X-ray spectroscopy, increases with the deposition angle. It is shown that the gold/titanium film with titanium deposited with an oblique angle of 50° is an optimized condition to obtain the largest sorption capacity after 1 h thermal activation at temperatures lower or equal to 300 °C. This film has a low initial residual stress that becomes highly tensile if thermal activation is performed above 300 °C. [ABSTRACT FROM AUTHOR]