Stress-induced anisotropy of phosphorous islands on gallium arsenide

The initial growth of ~234! phosphorous islands on ~432! terraces of gallium arsenide ~001! has been studied. The islands grow anisotropically in the @110# direction with an aspect ratio of approximately 8 to 1 at moderate coverages. The distribution of island widths in the @ 1̄10# direction follows a Gaussian function. The mean width increases from 2466 to 47611 Å as the phosphorous coverage increases from 0.10 to 0.85 monolayers. Evidently, the island anisotropy is caused by stress imposed on the underlying gallium layer by the smaller, more tightly bound phosphorous dimers. © 2000 American Institute of Physics. @S0003-6951~00!01640-5#