STRAIN DISTRIBUTION IN INP GROWN ON PATTERNED SI - DIRECT VISUALIZATION BY CATHODOLUMINESCENCE WAVELENGTH IMAGING

InP has been grown on patterned Si substrates using a low temperature metalorganic chemical vapor deposition process which insures compatibility with integrated circuit technology. Two different patterns are investigated: wet chemically etched V-grooves and SiO2-masked dry etched grooves. Reduction of feature size leads to drastic defect reduction and quantum efficiencies up to those of homoepitaxially grown InP. Strain relaxation and quantum efficiency are directly visualized by cathololuminescence wavelength imaging. On (001)- and {111}-facets of V-grooves distinct relaxation of the tensile thermally induced strain are found. Surprisingly, in the bottom of V-grooves, close to or even at the InP/Si interface, a high quantum efficiency is found with a recombination time constant typical for thick InP layers of high crystallographic quality.