THE GROWTH AND PROPERTIES OF AL AND ALN FILMS ON GAN(0001)-(1X1)

The growth, structure, and annealing behavior of Al films, formed by i n situ vapor deposition on GaN(0001)-(1X1) near 25 degrees C, have bee n studied using Auger, electron energy loss, x ray and ultraviolet pho toemission spectroscopies and low-energy electron diffraction. Film gr owth occurs by a Stranski-Krastanov process with reaction at the immed iate interface leading to metallic Ga. Annealing at >800 degrees C lea ds to release of N, which reacts with Al to form a (1X1)-ordered layer of AlN, possibly alloyed with a small. amount of Ga. The AIN layer ha s been characterized using the various spectroscopies, and the work fu nction, band bending, and electron affinity of GaN and of the AlN over layer have been obtained. The Al/GaN Schottky barrier height has been measured and compared with previous results for Ni/GaN.