DEVELOPMENT OF CHEMICAL BEAM EPITAXY FOR THE DEPOSITION OF GALLIUM NITRIDE

Modern approaches to the growth of high quality gallium nitride thin f ilms have focused on the use of metal-organic vapour phase epitaxy or plasma-assisted gas source molecular beam epitaxy. However, both of th ese techniques possess limitations. The present study therefore examin ed a new approach to GaN deposition using chemical beam epitaxy and th e new nitrogen precursor, hydrogen azide. Thin films of gallium nitrid e (GaN) were successfully prepared. X-ray photoelectron spectroscopy r eveals that stoichiometric material is formed with little or no contam ination when HN3 and a range of Ga precursors react on the substrate a t temperatures down to 450 degrees C. The results indicate that the in corporation efficiency of N in the GaN film from HN3 is high, suggesti ng the precursor may provide a more attractive route to the deposition of GaN films under low pressure molecular beam conditions than is cur rently offered using ammonia or plasma-excited nitrogen beam sources. Electrical measurements on the grown films are also reported.