Characterization of MOVPE‐grown GaN layers on GaAs (111)B with a cubic‐GaN (111) epitaxial intermediate layer

AbstractWe have proposed the use of cubic‐GaN (c‐GaN) as an intermediate layer for the metalorganic vapor phase epitaxy (MOVPE) growth of hexagonal‐GaN (h‐GaN) on GaAs (111)B substrates. Insertion of the c‐GaN layer at the h‐GaN (0001)/GaAs (111) interface significantly improves the crystallinity of the h‐GaN layer. Although, we have used [111]‐oriented c‐GaN layer so far, the lattice‐mismatch between h‐GaN (0001) and c‐GaN (111) is expected to be less than 0.1%, which is much smaller than that for the other commonly used substrate materials. Furthermore, the c‐GaN layer was grown at a relatively low growth temperature (Tg = 600 °C) to prevent the GaAs substrate from thermal decomposition and to provide a strain relief template layer. This technique enables us to succeed in obtaining nearly strain free h‐GaN layers on GaAs (111)B substrates. In this report, the relationship between the nature of the c‐GaN intermediate layer and the cubic‐to‐hexagonal structural transition machanisms are discussed. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)