GAS INCORPORATION DURING ION-ASSISTED DEPOSITION IN BIAS SPUTTERING

An important factor in ion-assisted deposition with ion guns or bias sputtering is the incorporation of gas atoms, particularly inert gas atoms, in the growing film. The incorporation of argon or xenon in sputtered films of chromium, molybdenum, and tungsten, produced using dc unbalanced magnetrons to provide the fluxes of depositing metal atoms and the ions has been studied as functions of bias voltage, ion-to-atom ratio, and in some cases temperature. The burial rate increased approximately as the square of the energy of the ions, and depended on the ion-to-atom ratio in a nonlinear way. The incorporation of energetic heavy ions in light materials was particularly pronounced. The temperature dependences of incorporation for Cr/Ar, Cr/Xe, and Cu/Ar are consistent with the inert gas atom residing substitutionally in the lattice.