• Proceedings of the Korean Vacuum Society Conference
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• 1998.02a
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• pp.129-129
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• 1998

Most of the surface/interface analysis tools have limited depth profiling c capability in terms of the profiling range and the depth resolution. However, M MEIS can profile the surface and subsurface composition and structure q quantitatively and non-destructively with atomic layer depth resolution. I In this presentation, the MEIS system developed at KRISS will be briefly d described with an introduction on the principle of MEIS. Recent MEIS r results on the surface and interface composition and structural change due to i ion bombardment will be presented for preferential sputtering of T:없Os and d damage depth profiles of SHooD, Pt(l11), and Cu(l1D due to Ar+ ion b bombardment. Direct observation of strained Si lattices and its distribution i in the SHool)-SiCh interface and the initial stage of Co growth on Pt(l11) w will be reported. H surfactant effects on epitaxial growth of Ge on Si(ooD w will be discussed with STM results from SND.

• Journal of the Korean Vacuum Society
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• v.17 no.3
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• pp.226-233
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• 2008

The nucleation and evolution process of Ge nano-islands on Si(001) surfaces grown by chemical vapor deposition have been explored using atomic force microscopy (AFM). The Ge nano-islands are grown by exposing the substrates to a mixture of gasses GeH4 and H2 at pressure of 0.1-0.5Torr and temperatures of $600-650^{\circ}C$. The effect of growth conditions such as temperature, Ge thickness, annealing time on the shape, size, number density, and surface distribution was investigated. For Ge deposition greater than ${\sim}5$ monolayer (ML) with a growth rate of ${\sim}0.1ML/sec$ at $600^{\circ}C$, we observed island nucleation on the surface indicating the transition from strained layer to island structure. Further deposition of Ge led to shape transition from initial pyramid and hut to dome and superdome structure. The lateral average size of the islands increased from ${\sim}20nm$ to ${\sim}310nm$ while the number density decreased from $4{\times}10^{18}$ to $5{\times}10^8cm^{-2}$ during the shape transition process. In contrast, for the samples grown at a relatively higher temperature of $650^{\circ}C$ the morphology of the islands showed that the dome shape is dominant over the pyramid shape. The further deposition of Ge led to transition from the dome to the superdome shape. The evolution of shape, size, and surface distribution is related to energy minimization of the islands and surface diffusion of Ge adatoms. In particular, we found that the initially nucleated islands did not grow through long-range interaction between whole islands on the surface but via local interaction between the neighbor islands by investigation of the inter-islands distance.