Sb and Bi surfactant effects on homo-epitaxy of GaAs on ( [formula omitted]) patterned substrates

Anisotropic lateral growth during GaAs ( 0 0 1 ) epitaxy can have dramatic effects on the evolution of patterned features and surface morphology. Many new opto-electronic devices require growth on patterned or non-ideal surfaces. Controlling lateral growth will be essential for the production of these devices. In this study, GaAs epilayers were grown by organometallic vapor-phase epitaxy on patterned GaAs ( 0 0 1 ) wafers. During these growth experiments, trimethylantimony and trimethylbismuth were used as surfactant precursors to investigate the effects of Sb and Bi on GaAs lateral growth rates. Both surfactants were found to enhance the [1 1 0] lateral growth rate by nearly 300 %, while having a negligible effect on the lateral growth rate in the orthogonal direction. Kinetic simulations assisted in determining a plausible surfactant mechanism: The enhanced [1 1 0] lateral growth rate is due to an increase in the frequency of [1 1 0] diffusion events (decreased hop barrier).