Characterization of the Microstructure of GaP Films Grown on {111} Si by Liquid Phase Epitaxy

The development of a cost-effective Si based platform on which III-V's can be grown is of great interest. This work investigates the morphology of gallium phosphide (GaP) films grown on {111} silicon (Si) substrates by means of liquid phase epitaxy in a tin (Sn) - based solvent bath. Two types of single-crystal {111} Si substrates were used; the first type was oriented exactly along the ⟨111⟩ surface (no-miscut) and the second was miscut by 4°. The growth rate of the GaP films was found to be markedly different for the two types of substrates; the GaP films on the miscut Si substrate grew ∼4 times faster than those on the no-miscut substrate. The GaP films grew epitaxially on both types of substrates, but contained Si and Sn as inclusions. In the case of the no-miscut substrate, a number of large Sn particles were incorporated at the GaP/Si interface. As a result, these interfacial Sn particles affected the strain state of the GaP films dramatically, which, in turn, manifested itself in the form of a duplex microstructure that consists of strained and strain-free regions.