INITIAL GROWTH OF GAAS ON VICINAL SI(110) SUBSTRATES

We report on the initial growth mechanism of GaAs on vicinal Si(110) s ubstrates grown by molecular beam epitaxy, for the first time, while c onsidering the effects of the substrate off-angle and direction on the crystalline quality of GaAs films. The quality was improved with an i ncrease of the off-angles, and was strongly influenced by the off-dire ction. The off-direction towards the [001] was better than that toward s [1 $($) over bar$$ 10] for obtaining high quality films. We believe that this is related to a difference in the step structure. We infer f rom the results of reflection high-energy electron diffraction, double -crystal X-ray diffraction, atomic force microscopy and plan view tran smission electron microscopy that GaAs films on vicinal Si(110), with off-angles of 5 degrees-7 degrees towards the [001] direction, grow re gularly along the [1 $($) over bar$$ 10] step edges at mono-atomic lay er steps. On these step edges, the films grow to a thickness of 3 nm i n a step flow like mode, and connect with each other through step-bunc hing at large steps having a height of 5 nm.