There is a great deal of interest in forming Au grains on semiconductor and insulating substratcs for device application. Reduction in density of grain boundaries is known to cause improvement of clectromigration in thin films. Transmission electron microscopy and diffraction have been used to study the growth behavior and morphology of vapor deposited Au on these substrates. Electron beam evaporation techniques were used to evaporate Au at high rates (50Å/sec or higher) on substrates held at low temperature (Rm. Temp. to 250°C). Large Au grains laave been found to form on both amorphous (Si3N4 and SiO2) and single crystal Si substrates. The grain size of Au was also found to be dependent on substrate surface roughness; rough surfaces tended to retard the formation of large grains. Grains as large as 1/2 μ in a matrix of smaller ones were observed in films as thin as 350Å Annealing up to 350°C, subsequent to deposition, did not appreciably increase the size of the larger grains, although the smaller ones grew by about 10%. The TEM analysis together with RBS and AES data showed no significant interaction between Au and Si (that is to say no atomic intermixing or silicide formation) under all deposition conditions as well as annealing heat treatments. The significance of this in relation to the growth behavior of Au on the insulating and single crystal Si substrates will be shown.