MECHANISTICS OF EARLY-STAGE GROWTH OF ALN ON ALUMINA .2. TMAL AND NH3

The reactions of trimethylaluminum (TMAl) and ammonia (NH3) on gamma-alumina were studied by Fourier transform infrared spectroscopy, thermal desorption spectroscopy, and X-ray photoelectron spectroscopy (XPS) to explore their feasibility as precursors for the low-temperature growth of AlN. Upon exposure of TMAl and NH3, covalently bonded Al-N networks are formed at room temperature. This reaction efficiency is enhanced by a factor of 4 when the NH3 is dosed with the substrate at 600 K. An atomic layer growth process involving cyclic processing at 600 K yielded site-specific reaction of the TMAl, followed by facile reaction of the ammonia to create new sites for the TMAl reaction. XPS results confirmed the presence of AlN.