We investigated structural perfection of porous gallium arsenide layers formed in GaAs (001). Different modes of electrochemical etching of n-type GaAs(001) substrates in fluoride-iodide aqueous electrolytes were used to form porous layers. Their structural properties were investigated by high resolution X-ray and synchrotron radiation diffraction and electron microscopy (SEM, TEM) techniques. It was shown that a single current pulse with a high magnitude forms a discontinuous porous layer with a smooth surface. Subsequent etching with a relatively low current density forms a homogeneous porous structure in the depth with approximately 30% porosity. The porous layer thickness can be varied from a few microns to several tens of microns depending on the etching time. The lattice parameter of porous GaAs layers along the surface normal is decreased by a factor of 1.5×10^-4 compared to the GaAs substrate. This contraction is related to the formation of vacancy type structural defects as revealed by the measurement of x-ray diffuse scattering.

Date Published: 8 January 2013
PDF: 7 pages
Proc. SPIE 8700, International Conference Micro- and Nano-Electronics 2012, 87000D (8 January 2013); doi: 10.1117/12.2017023

Published in SPIE Proceedings Vol. 8700:
International Conference Micro- and Nano-Electronics 2012
Alexander A. Orlikovsky, Editor(s)