GROWTH OF C-AXIS ORIENTED ALUMINUM NITRIDE FILMS ON GAAS SUBSTRATES BY REACTIVE RF MAGNETRON SPUTTERING

c-axis oriented aluminum nitride (AlN) films deposited on GaAs substra tes by reactive rf magnetron sputtering were fabricated. The structura l and morphological characterizations were found to be sensitive to th e deposition conditions including rf power, Nz concentration, sputteri ng pressure and substrate temperature. A highly c-axis oriented AIN hi m was. identified as low as 350 degrees C by x-ray diffraction. The cr ystallization of the AlN film with (002) preferred orientation tended to improve with increased rf power and N-2 concentration within the ex perimental range. A densely pebble-like surface texture of the c-axis oriented ALN films with an average grain size of about 80 nm was obser ved by scanning electron microscopy (SEM). The film showed a high degr ee of alignment of the columnar structure as was indicated by the cros s-sectional SEM photograph. The selected area diffraction pattern show ed that the deposited films exhibited a polycrystalline microstructure . (C) 1998 American Vacuum Society. [S0734-2101(98)04006-8].