Dopant-induced lattice dilation in n-type InP homoepitaxial layers

n-type Si- and Sn-doped InP homoepitaxial layers have been grown on (001) Fe-doped semi-insulating InP substrates by metal organic vapor phase epitaxy and liquid phase epitaxy, respectively. The net carrier concentration has been determined by conventional Hall measurements, while the total dopant concentration has been evaluated-by secondary ion mass spectrometry. The change in lattice constant has been carefully measured by x-ray double crystal diffractometry as a function of the dopant concentration. A lattice dilation has been observed for both dopants, but the Sn doping has been found to be about eight times less effective than the Si doping. The results could not be explained by Vegard's law. (C) 1996 American Institute of Physics.