Low Temperature Processing of TiN Epitaxial and Polycrystalline Films by Laser Physical Vapor Deposition

Abstract

We have investigated the formation of polycrystalline TiN films on (100) Si substrates and epitaxial (100)-oriented TiN films on (100) MgO substrates by laser physical vapor deposition. The films were deposited by excimer laser (wavelength 308 nm, pulse duration 45 nanosecond, and energy density 4-6 J cm-2 ) ablation of a TiN target pellet in high vacuum (~ 3.0 x 10-7 torn) with the substrate temperature ranging from 25 to 750°C. The epitaxial films on Mg° were obtained at relatively low substrate temperatures ( 450°C ) and polycrystalline films on Si were obtained at substrate temperatures ranging from 25 to 550°C. The deposited films were analyzed using cross-section and plan-view transmission electron microscopy, X-Ray diffraction, Rutherford backscattering / channeling patterns, Auger electron spectroscopy, and electron channeling patterns. Results for epitaxial film growth indicate <100> TiN parallel to <100> MgO with the minimum channeling yield( xmin ) < 10% and room temperature resistivity of 501.112-cm. Typical resistivity values of the polycrystalline films were 150 I. -cm and microhardness values were found to be as high as 17 GPa. The polycrystalline films are very dense with an average grain size of 100 A which remained approximately constant with substrate temperature up to 550°C. The polycrystalline films were of equiaxed nature with no preferred growth orientation. These microstructural features couple with low temperature deposition and dense nature make these films suitable for many advanced applications.