CRYSTAL-GROWTH AND MICROSTRUCTURE OF POLYCRYSTALLINE TI1-XALXN ALLOY-FILMS DEPOSITED BY ULTRA-HIGH-VACUUM DUAL-TARGET MAGNETRON SPUTTERING

Ti1-xAlxN alloy films with 0 less-than-or-equal-to x less-than-or-equal-to 1 were grown on thermally oxidized Si(001) substrates at a temperature T(s) = 500-degrees-C by dual-target ultra-high-vacuum reactive magnetron sputtering in pure N2. Films with 0 less-than-or-equal-to x less-than-or-equal-to 0.40 were single phase with a NaCl structure and an interplanar distance d002, determined by X-ray diffraction, that decreased linearly with increasing AlN content. Plan-view transmission electron microscopy revealed an open columnar structure with a relatively constant average grain size [d] of approximately 65 nm. As x was increased, the amount of intercolumnar pores or voids gradually decreased. X-ray diffraction pole figure measurements showed that with x = 0 (pure TiN) the columns were tilted approximately 24-degrees towards the source, which was located at an angle of 45-degrees to the substrate surface normal. However, increasing x to 0. 1 8 resulted in columns parallel to the substrate surface normal. Films with 0.40 < x less-than-or-equal-to 0.90 were two phase (NaCl and wurtzite structures) as judged by selected area electron diffraction. Phase separation was accompanied by a reduction in [d] to approximately 30 nm. The room temperature resistivity increased slowly for Ti1-xAlxN films with 0 less-than-or-equal-to x less-than-or-equal-to 0.40, and much more rapidly as the AlN content was increased further.