Berlin 2005 – wissenschaftliches Programm

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HL: Halbleiterphysik

HL 58: Poster IIb

HL 58.66: Poster

Dienstag, 8. März 2005, 16:30–19:00, Poster TU F

Formation of Ge dots on Si(111)-7x7 surface and effects of C predeposition using monomethylsilane — •Yuzuru Narita, Masashi Sakai, Takeshi Murata, and Maki Suemitsu — Center for Interdisciplinary Research, Tohoku University, Aramaki aza-Aoba, Aoba-ku, Sendai 980-8578, Japan

Germanium (Ge) dots are promising as a new material for Si-based opto-electronic integrated circuits (OEICs). To reduce the size of the Ge dots on Si, carbon (C) predeposition prior to Ge deposition has recently proved itself. Most of previous studies, however, have used solid-source MBE for both C and Ge depositions, which may be problematic when applied in practical use. Also, few studies have ever been made on Si(111)-7x7 surface, which could nevertheless affect the adsorption and diffusion of Ge atoms and therefore be a possible template for dot alignment. In this study, we have formed Ge dots on Si(111)-7x7 surface by using germane and monomethylsilane (MMS) as Ge and C sources, respectively. By exposing the Si(111)-7x7 surface at RT to 80-L MMS flux and by desorbing the surface hydrogen with an anneal at 900C for 1 min, the subsequent dot density increased about two orders of magnitude and the dot size decreased by a factor of six as compared to the case without the C predeposition. From the Raman-scattering microscopy, the Ge dots formed with C predeposition using MMS are found to be nearly dislocation-free.