A microscopic investigation of the structural features of polyethylenetherephthalate (PET) films with thin golden layers deposited by the ion-plasma method has been carried out. It is shown that a continuous metallic layer does not arise on a polymer surface under an effective thickness of metallic coating of 5–7 nm or less. In this case the metal condenses in the form of nanoparticles (the size of which depends on the polymer-substrate nature, time of deposition, etc.,) and these nanoparticles are separated by pure polymer layers. Nevertheless, the process of deformation of gold-coated PET films is accompanied by fragmentation on the surface polymer-substrate irrespective of the effective thickness of the coating. In spite of the fact that a continuous metal phase is not formed on the surface of polymer at small deposition times (small effective thickness), but a certain layer that behaves as a monolithic unit on the polymer surface. The tensile elongation of this layer is less in comparison with polymer—substrate; therefore there is a fragmentation during polymer-substrate deformation similar to the case of fragmentation of other firm coverings. The reasons for the revealed phenomenon are not quite clear, and it is necessary to carry out an additional investigation in order to understand how it works.