SURFACE-STRUCTURE CONTROL OF GAAS (111)A VICINAL SUBSTRATES BY METAL-ORGANIC VAPOR-PHASE EPITAXY

Periodic structures with high uniformity have been fabricated by metal -organic vapor-phase epitaxy on GaAs(111)A vicinal surfaces. Scanning electron microscope and atomic force microscope surface images show st rict dependence on substrate off-direction, growth temperature (T-g), and V/III ratio. Giant steps with long-range continuity and high unifo rmity have been formed on GaAs (111)A substrates misoriented towards t he [112] direction. In addition, the heights of the giant steps show t he saturation at high T-g: and the value is independent of substrate o ff-angle, On the other hand, homogeneous zigzag steps have emerged on the substrate off toward the [001] azimuth after the growth at high T- g, whereas relatively rough steps were formed on both substrates at lo w T-g. The results indicate the growth-mode transition from step-flow to facet formation as growth temperature gets higher.