The formation of antiphase domains in GaAs on Ge(001), misoriented towards <110>, was studied as a function of the substrate misorientation angle, growth rate, V/III ratio and growth temperature. The domains were revealed by means of chemical etching, transmission electron microscopy and optical interference contrast microscopy. It was found that the substrate misorientation played the most important role in determining the size and shape of antiphase domains. With increasing misorientation angle, the size of the antiphase domains in the epilayer decreased. In the case of layers on substrates with misorientation angles of more than 0.4, all of the antiphase boundaries annihilated within a thickness of 4; with no antiphase domains being visible at the top surface. More regularly shaped antiphase domains developed as the misorientation angle approached zero. The growth rate and the growth temperature also had an effect upon the formation of antiphase domains. All of these effects could be explained in terms of the step-terrace nucleation model for polar/nonpolar hetero-epitaxy. The formation of antiphase domains in the epilayer could be completely suppressed by using a V/III ratio of 60, and a 3 misorientation. The presence of antiphase domains in layers which had been grown on 3-misoriented substrates at lower V/III ratios indicated that an AsH3 partial pressure of 2mbar was required in order to ensure an antiphase domain-free epitaxy of GaAs on Ge.

Y.Li, G.Salviati, M.M.G.Bongers, L.Lazzarini, L.Nasi, L.J.Giling: Journal of Crystal Growth, 1996, 163, 195-202