ERBIUM SILICIDE FILMS ON (100) SILICON, GROWN IN HIGH-VACUUM - FABRICATION AND PROPERTIES

High crystalline quality Erbium silicide films with preferred orientat ion on (100) Si were obtained by (a) erbium deposition on Si in high v acuum and (b) co-deposition of Er and Si in a flux ratio of Si/Er clos e to 2 and subsequent annealing. Erbium silicide layers of thickness a round 50 nm were obtained, which were characterized by X-ray diffracti on, Rutherford backscattering spectroscopy (RBS), scanning electron mi croscopy and electrical measurements, including both resistivity measu rements at room and low temperatures and current-voltage measurements on specially prepared Schottky diodes. High crystalline quality (only one orientation in the X-ray diffraction pattern) was obtained in case (a). Films of case (b) seem to be polycrystalline from the X-ray diff raction pattern but they show high channelling yield in channelling RB S. This is attributed to a first layer of good crystalline quality on silicon and a surface layer of less good crystallinity on top. Reduced surface and interface roughness was also obtained in case (b), result ing in current-voltage characteristics corresponding to an ideality fa ctor close to 1.