Amorphous or nanocrystalline AlN thin films formed from AlN: H

Abstract

This work describes the formation of stoichiometric AlN films by single ion-beam sputtering of Al, using an ionized N2 (75%) + H2 (25%) mixture, onto substrates heated to 200 °C or above. The role of substrate temperature on film composition and properties is followed in the substrate temperature range between ambient and 250 °C. Infrared 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 ≥200 °C are very smooth and highly resistant to attack by atmospheric gases. X-ray diffraction data show no diffraction peaks, indicating that the film is either amorphous or crystalline on a scale of less than 4 nm.