POLYCRYSTALLINE TIN FILMS DEPOSITED BY REACTIVE BIAS MAGNETRON SPUTTERING - EFFECTS OF ION-BOMBARDMENT ON RESPUTTERING RATES, FILM COMPOSITION, AND MICROSTRUCTURE

Transmission electron microscopy, x-ray diffraction, and Rutherford backscattering have been used to investigate the effects of ion irradiation during growth on the deposition rate, composition, and microstructure of single-phase polycrystalline NaCl-structure TiN(x) films deposited by reactive magnetron sputtering with a negative substrate bias voltage V(s). The layers were deposited on thermally oxidized Si(001) substrates in mixed Ar + 4% N2 discharges at a total pressure of 4.2 mTorr. Varying V(s) between 0 and 1800 V resulted in incident ion-to-Ti atom flux ratios of 0.3 to 0.6 at the film growth surface and increases in the substrate temperature T(s) (initially T(s) = 300-degrees-C) of 40 to 200-degrees-C. The Ti resputtering yield increased from less-than-or-equal-to 0.02 (V(s) less-than-or-equal-to 100 V) to 0.30 (V(s) = 1800 V) Ti atoms per incident ion (primarily Ar+), while the N/Ti ratio in as-deposited films increased from 1.03 for V(s) = 0 V to 1.12 for 100 V less-than-or-equal-to V(s) less-than-or-equal-to 400 V and then decreased to congruent-to 0.95 as V(s) was raised to 1800 V. Trapped Ar concentrations ranged from less-than-or-equal-to 0.5 at.% (V(s) = 0) to congruent-to 5.5 at.% (V(s) = 1800 V). However, the Ar was not randomly dispersed in films grown with V(s) > 1000 V and gas bubbles were observed. Film lattice parameters a0 were found to vary from the bulk value of 0.4240 nm at V(s) = 0 to a maximum of 0.4295 nm at V(s) = 800 V and then decrease to 0.4265 nm at V(s) = 1800 V. Voided grain boundaries were observed in films grown with V(s) less-than-or-equal-to 120 V. The use of higher substrate biases initially resulted densification of grain boundaries with a corresponding decrease in average grain size. However, with V(s) greater-than-or-equal-to 800 V, the films again became less dense and increased intragranular defect densities were observed.