Thin Film Nucleation and Growth Under Controlled Conditions

Abstract

Results of controlled in-situ nucleation experiments inside the electron microscope were reported recently. The experimental technique employed permitted detailed quantitative studies of the nucleation kinetics which led to a comparison of test results with nucleation theoretical predictions. However, the background pressures were still of the order of 10-7 to 5x10-8 torr and the experimental arrangement did not provide for producing and maintaining clean single-crystal substrates. It was therefore necessary to limit the choice of substrate-overgrowth material combinations, delete epitaxial studies completely, and defer meaningful investigations of the effect of residual gases on nucleation and growth processes. In addition, the influence on the experimental results of the high-intensity imaging electron beam could only be assessed in a qualitative manner.A research program involving two methodically different experimental approaches has since been initiated that promises to eliminate most of the previous test restrictions. The two approaches entail the use of a modified low-energy electron diffraction (LEED) system in conjunction with extraction replica electron microscopy, and a newly designed ultrahigh-vacuum (UHV) electron-microscope specimen chamber in combination with a microscope image intensifier system for in-situ deposition studies.