Abstract

A memory device and method is disclosed wherein positions of ions associated with a film are varied locally with respect to the film's surface by an electric field. A writing and erasing field is created by voltage modulating the film's conducting substrate in syncronization with low intensity electron bombardment of a local area of the film's surface by a scanning electron beam.The ion's position in the film varies the film's surface potential and alters the angular distribution imparted by its surface to primary diffracted and secondary emitted electrons. In the invention's read mode a scanning electron beam, combined with a detector discriminator, analyzes these emitted electrons to determine the surface potential at each address on the film thus reading out data stored in the film. A second means of reading out stored information utilizing detection of low energy electrons selectively diffracted by ions near the film's surface is disclosed.