Measurement of misorientation of AlN layer grown on (111)Si for freestanding substrate

A novel technique for misorientation determination based on energy dispersive X-ray diffraction is introduced. The energy dispersive diffractometer equips with a silicon drift detector as a energy dispersive detector and a micro focus air cooled X-ray tube as a source. The diffractometer has advantages in speed of measurement and alignment of sample compared with conventional angular dispersive diffractometer. Dependence of misorientation of AlN layers on misorientation angle and direction of (111) Si starting substrates were investigated by this method. It is found that the AlN has (0001) orientation and the (0001) plane is tilted when the film thickness is thin. Moreover, it is shown that the tilt becomes smaller with increasing the film thickness. The atomic force microscopy (AFM) showed clear difference in surface morphology of obtained AlN layer depending on misorientation direction of Si substrate. The AlN film grown on (111) Si with 1 degree misorientation angle toward [1 12] showed the best step and terrace structure compared with those grown on that having larger than 1 degree misorientation angle. (C) 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim