US 4,287,572 AGranted

Method for writing on archival target and target produced thereby

AssigneeGeneral Electric Company

InventorHarold F. Webster

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Abstract

A method for storing data in an archival memory semiconductor target by providing a masking layer of a conductive material on the surface of an insulative layer upon the top surface of a semiconductor substrate; the material layer is assigned a two-dimensional array of possible data storage sites. The masking layer at those storage sites at which a first binary value is to be stored, is melted; the selected material is one which, at the melting temperature thereof, does not wet the surface of the chosen insulator whereby apertures are formed by the writing electron beam in the masking layer, at energy levels insufficient to evaporate the masking material. The writing beam energy is reduced at the data sites at which data bits of the remaining binary value are to be stored, and does not melt the masking material thereat. The data stored in the target is read by sweeping an electron beam of relatively low energy across the array to induce a flow of current from the semiconductor substrate and of magnitude dependent upon the presence or absence of an aperture in the masking layer at the data site interrogated.

Claims17

Dependent claims

A method for archival memory recording of data, comprising the steps of:

(a) providing a semiconductor substrate having a surface;
(b) fabricating a layer of insulative material upon said semiconductor substrate surface;
(c) selecting a conductive material which does not, when molten, wet the surface of the insulative layer;
(d) fabricating a layer of the selected non-wetting material upon the insulative material layer surface furthest from the substrate;
(e) assigning a two-dimentional array of potential data storage sites upon the surface of the masking layer furthest from said insulative layer;
(f) directing a beam of electrons sequentially to each of at least a portion of the array of potential data storage sites;
(g) imparting sufficient energy to the electrons of said beam to melt the material of said masking layer when said beam impinges at each data storage at which a first binary value of data is to be stored;
and
(h) imparting another value of energy to the electrons of said beam, insufficient to melt the material of said masking layer, when said beam impinges at others of the potential data storage sites of said array at which a remaining value of binary data is to be stored.

6 more elements

Dependencies are inferred from the claim text.