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Charge Storage Beam Addressable Memory

IP.com Disclosure Number: IPCOM000094419D
Original Publication Date: 1966-Oct-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 65K

Publishing Venue

IBM

Related People

Beam, WR: AUTHOR

Abstract

A sandwich structure of semiconductive and insulating materials is irradiated at selected points while under the influence of applied electric fields to store charges representing data bits. Reading of the stored bits is accomplished by irradiating the semiconductor at selected points and observing the resultant discharge current if any.

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Charge Storage Beam Addressable Memory

A sandwich structure of semiconductive and insulating materials is irradiated at selected points while under the influence of applied electric fields to store charges representing data bits. Reading of the stored bits is accomplished by irradiating the semiconductor at selected points and observing the resultant discharge current if any.

Sheet 3 composed of a radiation-sensitive charge-storing semiconductor, e.
g., amorphous selenium, is sandwiched between layers 2 and 4 of insulating materials such as amorphous tantalum or niobium oxide. Such materials have extremely low conductivities and can be made in uniformly thin layers. The sandwich is enclosed between outer metal layers 1 and 5. These serve as electrodes for applying voltages across the thickness of the sandwich structure.

Metal layer 1 is thin enough to transmit the addressing beam. Layers 2 and 3 likewise are transparent to this beam. Layer 4, which is optional depending upon the mode of operation, and layer 5 need not be transparent. Electrode 5 can be made sufficiently thick and rigid to serve as a support for the structure. The mode of operation is as follows.

To perform writing, the beam is directed at any selected spot in semiconductor 3 while device 6 applies an electric field of selected polarity, representing 1 or 0, across layers 1 and 5. Semiconductor 3 becomes locally conductive at the point where it is addressed by the beam, causing localized charges t...