Synchrotron radiation multiple diffraction study of Al_0.304Ga_0.172In_0.524 As MOVPE grown onto InP(001)

Synchrotron radiation multiple diffraction in Renninger scanning (RS) geometry is used to characterise an Al_0.304Ga_0.172In_0.524As hetero-epitaxial layer MOVPE grown onto InP(001). (006) RS data for bulk, InP substrate and the quaternary layer were obtained using a new experimental set-up on station 7.6 at the Daresbury synchrotron radiation source. Examination of the multiple diffraction peak profiles reveal the epitaxial layers to have a higher mosaic spread than the underlying substrate materials. Measurements of the layer parallel lattice parameter a_? = 5.8755 ± 0.0003 Å, as deduced from the tetragonal distortion measured at the 6-beam case in the layer RS, agrees very well with that obtained from the 222 222 intensity modulation on the substrate RS MORSI (modulation on the RS intensity due to the presence of the epilayers, Greenberg and Ladell, Appl. Phys. Lett 50 (1987) 436), which gives a_? = 5.877 ± 0.002 Å. Simulation of the layer RS using the MULTX program is consistent with a layer normal lattice parameter a_? = 5.8574 Å in good agreement with the corresponding experimental data.