Investigation of polarity dependent InN{0001} decomposition in N2 and H2 ambient

Abstract

AbstractThe polarity dependence of decomposition of the (0001) In‐ and (000$ \bar 1 $) N‐polarity InN layers grown by hydride vapor phase epitaxy (HVPE) on freestanding GaN substrates was investigated. In flowing N2, In‐ and N‐polarity InN layers start to decompose over 550 and 610 °C, respectively. Therefore, the N‐polarity InN layer is more stable than the In‐polarity InN layer. On the other hand, in flowing H2, InN layers of both polarities start to react with H2 at a low temperature of 350 °C leaving In droplets on the surfaces. Further more, the decomposition rate of the N‐polarity InN layer is larger than that of the In‐polarity InN layer below approximately 450 °C, while the decomposition rate of the In‐polarity InN layer is larger than that of the N‐polarity InN above 450 °C. An Arrhenius plot of the decomposition rates revealed that the activation energies, EA, for the decomposition reactions of In‐ and N‐ polarity InN layers are 168 and 107 kJ/mol, respectively, which are much smaller than that for GaN and AlN decomposition. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)