Changes in the morphology and structure of the GaAs surface during the deposition of an Au film by thermal evaporation in vacuum have been studied. It has been found that the deposition of an Au film with the participation of a flow of particles and light from a heated evaporator causes the appearance of photo effects in the near-surface GaAs layers, including light diffraction on surface acoustic waves, the growth of whiskers, and electron emission, which leads to the formation of microcracks on the GaAs surface and the growth of GaAs crystallites. It is shown that the structure and composition of the film boundaries of Au and GaAs surfaces depend on the electron concentration in gallium arsenide, which ultimately determines the properties of the electrophysical parameters of the Au-GaAs contacts.