Deposition of zirconium boride thin films by DC-triode sputtering.

Specular, crackfree thin films of the refractory conductor zirconium boride have been deposited for possible applications in combined contact/diffusion barrier metallization schemes. Films were deposited by d.c.triode sputtering, which allowed the independent study of the effects of sputtering pressure, target voltage and current on the film properties. At a fixed voltage and sputtering pressure the deposition rate increases almost linearly with target current. The mole ratio of boron in the films increased (composition tending to ZrB(2)) and the resistivity decreased with increasing deposition rates. Decrease in sputtering pressure, with only a minor change in deposition rate, dramatically decreased resistivity and caused stress in the films to change from tensile to compressive. Triode sputtering permitted deposition of films at 2 mtorr with a resistivity of 162micronomega-cm which is the lowest reported value for as-deposited films.