A new type of electron beam activated switch (EBAS) is described which utilizes electron beam induced charge storage in the metal-oxide-semiconductor (MOS) system. The state of the EBAS is determined by monitoring the surface conductance of the semiconductor. After discussing the basic charge-storage phenomena, memory arrays that use the electron beam for storing and reading information are described. A matrix array of EBASs in which information is stored using the electron beam and read by row-column access circuits is discussed in detail. The time to store a bit of information is a function of the current density of the electron beam; an approximate dosage of 10-5C/cm2is required for storage. A memory design using Schlesinger's microspot tube for the electron optics is discussed. It is shown that storage of 1.0 × 107bits per tube should be possible with presently available electron optical design and semiconductor technology.