EFFECT OF BEAM VOLTAGE ON THE PROPERTIES OF ALUMINUM NITRIDE PREPAREDBY ION-BEAM-ASSISTED DEPOSITION

The effects of nitrogen-beam voltage on the structure, stress, energy band gap and hard ness of AIN thin films deposited on Si (111), Si (10 0) and sapphire (0001) by ion beam assisted deposition (IBAD) are repo rted. As the nitrogen-beam voltage was increased from 50 to 200 V, the stress and disorder in the AIN films increased as determined by X-ray diffraction, FTIR and Raman spectroscopy. The preferred orientation o f the film's c-axis changed from completely normal to the film at 100 V, to a mixture of normal and in the plane of the film at 200 V. For A IN films deposited under the same conditions, the films were more high ly oriented on sapphire (0001) than in Si (111). The hardness of the f ilms increased from 18.2 to 23.7 GPa with the nitrogen-beam voltage, a nd possible reasons for this change in hardness are considered.