In-situ dynamical experiments in the transmission electron microscope (TEM) have long interested electron microscopists. In designing and performing the experiments, it is important to minimize the influences of the factors, which include the specimen thickness, electron beam heating, electron irradiation and specimen environments that may affect the validity of in-situ experiments. Comparisons of the results with those of other experiments are also very desirable.In microelectronic device fabrication process, it has become increasingly common to react a few hundred Å in thickness metal films with silicon substrate to form silicide contacts. Ni thin films on silicon have been chosen for in-situ annealing study since this system has been extensively investigated by Rutherford backscattering and glancing angle x-ray experiments. In-situ annealing of Co, Mo, Ti, Pd and W thin films on silicon have also been performed.Ni films, 300 and 400 Å thick, were electron gun deposited on (001) n-type silicon. Thin foils for TEM examination were chemically polished from silicon side. A JEOL 100B microscope equipped with a side entry, single tilt hot stage was used for TEM study.