Quantum chemical mechanism in parasitic reaction of AlGaN alloys formation

The mechanism of parasitic reactions among trimethylaluminum (TMA), trimeth ylgallium (TMG), and NH3 in atmospheric pressure (AP) MOVPE for growth of A lGaN is theoretically studied using the quantum chemical method. The calcul ations show that metal-nitrogen chain growth reaction easily proceeds throu gh the successive reactions of 'complex formation with NH3' and 'CH4 elimin ation by the bimolecular mechanism'. Additionally, a parasitic reaction in APMOVPE using other raw material is also investigated. The calculated resul t shows that small change of raw material raises activation energy of paras itic reaction, and, thus, the parasitic reaction is suppressed. This result suggests a way to improve APMOVPE by a suitable choice of substituent. (C) 2000 Elsevier Science B.V. All rights reserved. PACS: 81.10.Aj, 31.15.Ar; 82.30.Eh.