OPTICAL AND PHYSICAL-PROPERTIES OF SPUTTERED SI-AL-O-N FILMS

Mechanical and optical properties and structural characteristics are described for Si : N films with Al and O additions (SixAl1-xOyN1-y) deposited by reactive RF diode sputtering on Si and SiO2 substrates. The thermal and intrinsic stress components, elastic stiffness, coefficient of thermal expansion (CTE), and refractive index were measured for films ranging in thickness from approximately 2-mu-m to 50-mu-m. Some structural and microstructural data were obtained using x-ray diffraction, optical and scanning-electron microscopy, and surface profilometry. Alloying Si : N with Al to form Si : Al : N greatly reduced the compressive intrinsic and total stress found in pure Si : N films on Si. Addition of O to the Si : Al : N moderately increased the intrinsic stress, decreased the elastic stiffness, and produced a smoother, more glassy (amorphous) film.