Preprogrammed Non-Volatile Metal-Oxide-Semiconductor Memory by Use of Ionizing Radiation

A technique of "burning in" a preferred state in Metal-Oxide-Semiconductor (MOS) memory cells using ionizing radiation such as electron bombardment or X-rays is described. When the memory power is removed and reapplied, the memory will always configure itself to the preset information pattern while still allowing normal electrical alteration of stored information in either random access memory (RAM) or shift register configuration memory chips. Potential applications of this data "burn in" technique are as an additional or improved method of fabrication of read only semiconductor memories (ROM) and reprogrammable read only memories. Considerable application also exists for a memory which can be caused to turn on in a particular information pattern each time power is interrupted and reapplied and still operate after turn on as an ordinary electrically alterable memory.