Growth of GaAs on GaAs-coated Si by liquid-phase epitaxy

The liquid-phase-epitaxial growth of GaAs on partially masked GaAs-coated Si substrates prepared by molecular-beam epitaxy is described. Uniform layers were obtained in stripe windows narrower than 20 μm at an optimum growth temperatures of 800 °C. Smaller supercooling, however, resulted in smoother surface morphologies. The growth can be explained in terms of the mass transport of the growing species from bulk of the melt to the substrate surface and the subsequent incorporations into the solid. A marked difference between the growth on GaAs-coated Si and that on GaAs substrates was observed. The growth on GaAs substrates appears to be dominated by surface reaction while transport processes are the limiting factor on GaAs-coated Si. The migration length of the growing species was estimated to be very short on GaAs substrates and about 15 μm on GaAs-coated Si.