Epitaxial growth of AlN on (La,Sr)(Al,Ta)O-3 substrate by laser MBE

We have grown aluminum nitride (AlN) on LSAT substrates for the first time using laser MBE and investigated its growth mechanism. It has turned out th at surfaces of LSAT substrates become atomically flat by annealing in a UHV chamber. Reflection high energy electron diffraction observations and AFM measurements have shown that the growth of the AIN film starts with two-dim ensional amorphous growth followed by three-dimensional epitaxial island gr owth. The epitaxial relationship between AlN and LSAT substrates is AlN(0 0 0 1)parallel to LSAT(1 1 1) and AlN[1 1 (2) over bar 0]parallel to LSAT[0 1 (1) over bar], which is rotated from the expected lattice matched alignme nt by 30 degrees along AlN[0 0 0 1]. X-ray diffraction measurements have re vealed that the crystalline quality of the AlN film grown on LSAT is superi or to that on a conventional Al2O3 substrate. (C) 2001 Elsevier Science B.V . All rights reserved.