Polar-on-nonpolar epitaxy
Herbert Kroemer

Journal of Crystal Growth, Volume 81, Issues 1-4, Pages 193-204 (1987)

Abstract
One of the most fundamental problems that must be solved if device-quality GaAs is to be grown on Si substrates is that of suppressing antiphase disorder. Recent experimental evidence shows that such disorder can be suppressed not only on the (211) orientation, but also on (100), contrary to earlier theoretical expectations. A detailed discussion is given of the mechanism by which this suppression takes place, through a combination of slight misorientation and a high-temperature surface anneal, which lead to the pairing of all Si surface steps into a particular kind of double-height steps. A recent model by Aspnes and Ihm explains the energetic preference for this kind of step by postulating a drastic reconstruction of the atomic configuration at the step edge through the formation of a π-bonded chain running along the step. Another unexpected puzzle is posed by the recent observation that on a given Si(100) surface antiphase disorder-free growth with both possible Ga—As sublattice allocations can be achieved, depending on initial nucleation conditions. A new detailed nucleation model is proposed that explains these observations, by drawing heavily on earlier considerations of Harrison et al. concerning the electrostatics of a polar-nonpolar interface.