AMORPHOUS OR NANOCRYSTALLINE ALN THIN-FILMS FORMED FROM ALN-H

This work describes the formation of stoichiometric AlN films by singl e ion-beam sputtering of Al, using an ionized N2 (75%) + H-2 (25%) mix ture, onto substrates heated to 200-degrees-C or above. The role of su bstrate temperature on film composition and properties is followed in the substrate temperature range between ambient and 250-degrees-C. Inf rared spectra of freshly prepared and 2 month old (aged in air) films demonstrate that substrate heating significantly affects the chemical nature of the resulting films. SEM and STM data, combined with IR and UV-visible spectral results, indicate that films formed at a substrate temperature of greater-than-or-equal-to 200-degrees-C are very smooth and highly resistant to attack by atmospheric gases. X-ray diffractio n data show no diffraction peaks, indicating that the film is either a morphous or crystalline on a scale of less than 4 nm.