ALTERNATIVE PRECURSOR SYSTEMS FOR THE MOCVD OF ALUMINUM NITRIDE AND GALLIUM NITRIDE

Two alternative precursor systems have been investigated for the growt h of AlN and GaN by MOCVD. The first involved the reaction between Me( 3)M (M=Al, Ga) and tert-butylamine ((BUNH2)-B-t), whilst the second ro ute involved the pyrolysis of single-source precursors such as Me(3)M( NH3) (M=Al, Ga) and [Me(2)Ga(NH2)](3). Both routes proved suitable for the deposition of AlN thin films, and epitaxial AlN layers have been deposited on sapphire (0001) from Me(3)Al(NH3) without any added NH3. Attempts to grow GaN from Me(3)Ga/(t)BuNH(2) mixtures or Me(3)Ga(NH3) were unsuccessful, leading to the deposition of Ga droplets, although GaN films containing a large excess of Ga were deposited by low-pressu re MOCVD from the single-source precursor [Me(2)Ga(NH2)](3).