STRESS AND RESISTIVITY OF TA-MO AND TA-W SPUTTERED THIN-FILMS

Mo or W doping of sputtered Ta films resulted in the phase transition from tetragonal to cubic and significantly varied stress and resistivi ty. Prior to complete transition, films consisting of two phases exhib ited stress relaxation, and tended to transition to the cubic phase wi th subsequent annealing. With the complete transition to the cubic pha se, films showed an increase in stress. Resistivity was approximately 10-30 muOmega-cm for cubic films, while that for tetragonal films was measured to be 120 muOmega-cm. We determined pure Mo films to be suita ble as electrodes due to their lower resistivity, lower stress and bet ter thermal stability in Ta-Mo alloy systems. The proposed Ta-Mo and T a-W films exhibited the very small stress required for utilization as X-ray absorbers for X-ray photolithographic masks caused by the relaxa tion due to coexistence of cubic and tetragonal phases.