Control and understanding provide the two primary motivations for in-situ film characterization. For vacuum deposition, one powerful in-situ probe is the high-energy electron beam. Reflection High-Energy Electron Diffraction(RHEED) is a well-known method, used in Molecular Beam Epitaxy(MBE), for both purposes. Direct imaging using high energy electron beams forms the basis of transmission electron microscopy (TEM), which provides far more microstructural information than RHEED. Due to the instrumental complexity and invasiveness of the technique, however, in-situ TEM is directed at understanding, rather than controlling growth. I illustrate with examples from my group's work which includes: understanding the growth of very thin oxides, both on metals@footnote 1@ and semiconductors;@footnote 2@ the nature of small particle sintering in the formation of nanophase metallic thin films;@footnote 3@ island growth and stress@footnote 4@ in epitaxial Ge on Si; and AlN epitaxy on sapphire.@footnote 5@ The emphasis is that understanding through in-situ microscopy can lead to control, without in-situ probes, through better understanding of growth processes.
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@footnote 1@J. C. Yang and J. M. Gibson, Appl. Phys. Lett. 70, 3522 (1997). @footnote 2@X. Chen and J. M. Gibson, Appl. Phys. Lett. 70, 1462 (1997). @footnote 3@M. Yeadon, J. C. Yang, M. Ghaly, D. Olynick, R. Averback, and J. M. Gibson, Appl. Phys. Lett. 71, 1631 (1997). @footnote 4@R. D. Twesten and J. M. Gibson, Phys. Rev. B 50, 17628 (1994). @footnote 5@M. Yeadon, M. T. Marshall, F. Hamdani, S. Pekin, H. Morkoc, and J. M. Gibson, Journal of Applied Physics 83, 2847 (1998).