Robert J. Nemanich*, Woochul Yang, and Harald Ade
Department of Physics and Department of Materials Science and Engineering North Carolina State University, Raleigh, NC 27695-8202
It is evident that future electronics will require control of film growth processes on a nanometer scale. To date there are few techniques that have the capability for in situ, real time measurements of the dynamical processes that occur during growth and processing on semiconductor surfaces. Many of these processes occur at surface temperatures as high as 1100C. The combination of tunable UV excitation and a high resolution electron emission microscope can enable these measurements. This combination has been achieved at the Duke University FELL with the development of a high resolution photo-electron emission microscope (PEEM). The UV PEEM offers the capability of tuning the photon energy to the work function of the appropriate material on the surface, thus obtaining high contrast images at temperatures greater than 1100C. In this study we report the first observations of the dynamics of liquid Pt-Si islands on Si(100) surfaces. The dynamics of coalescence is observed. Moreover, a driving force for motion of the liquid micro-droplets is developed based on these observations. We also report initial studies of the dynamics of growth of nm scale TiSi2 islands on Si(111) and Si(100). Depending on the growth conditions, we observe ripening or coalescence processes where smaller islands evolve into larger islands. On the (111) surface a shape transition is observed in which the islands are initially circular and then develop into long wire shaped structures. The growth processes represent a competition between kinetic and energetic processes on the surfaces.
