Interface supersaturation in microchannel epitaxy of InP

By employing microchannel epitaxy (MCE), it became possible to reduce the d islocation density in liquid phase epitaxy (LPE) of InP so that steps suppl ied from only one screw dislocation can cover the whole surface of MCE isla nd. This enabled us to measure interstep distance by AFM and to calculate i nterface supersaturation even in metallic solution with the help of Cabrera and Levine formula by assuming appropriate value of interface free energy. The interface supersaturation was found being ranged from 0.02 to 0.05 upon various experimental conditions. A minimum interface supersaturation was r ealized when the growth temperature and cooling rate were chosen as 500 deg rees C and 0.05 degrees C/min, respectively. The ratio of width to thicknes s of the grown MCE layer, which is defined as WIT ratio, was found to incre ase rapidly with the decrease of the interface supersaturation. A WIT ratio as high as 20 was accomplished under the growth condition where minimum in terface supersaturation can be realized. (C) 1999 Elsevier Science B.V. All rights reserved.