The structures of thin films of RbAg4I5and CsAg4Br3-xI2+x, vacuum deposited on thin carbon supports, were investigated in a scanning transmission electron microscope. It has been found that a phase with a high ionic conductivity (solid electrolyte) formed in annealed films is very sensitive to electron irradiation. The use of a focused electron beam is demonstrated to produce directly features in films of the solid electrolytes.