Abstract: A CMOS ROM is fabricated and programmed using a two-metal fabrication process which is substantially equivalent to a conventional CMOS polysilicon gate manufacturing technique so that the CMOS ROM is advantageously fabricated in the same process steps that are used to fabricate the other, non-ROM circuits on an integrated circuit chip. In this method, multiple bit-lines in a first metal layer are formed which overlie a substrate containing the array of transistors. The bit-lines are connected to drain regions of the transistors. A dielectric insulating layer is formed over the substrate and the bit-lines and the dielectric insulating layer is perforated by vias which allow connecting to the first metal layer. Multiple word-lines and multiple reference voltage lines are formed in a second metal layer overlying the dielectric insulating layer. Either a word-line or a reference voltage line is programmably selected to connect to the gate of a transistor for each transistor of the multiple transistors.

Abstract: A memory is formed from an array of switchless integrated circuit memory cells in a high-density configuration. These cells comprise a capacitor and two diodes in a configuration where one diode is used to charge one pole of the capacitor, and the other diode is used to discharge it from that same pole, over separate paired lines used respectively for charging and discharging, as well as reading. The other pole of the capacitor is tied to a single line used for both charging and discharging, and in support of reading. Drive and sense circuitry located at the periphery of the cell array is used to perform interconnect switching functions while writing or reading charges on cells in the array. Alternative high-density switched cell variations are also described. The cell arrays are fabricated on monolithic integrated circuits which are interconnected with one another by using a method which deposits and etches conductive material which links conductive traces between the monolithic dice.

Abstract: A method and system for programming vROM programmable memories using antifuses fabricated from undoped amorphous silicon as a high resistance link or layer between two metal layers. Whenever a programming voltage higher than a normal operating voltage is applied across the link between the two metal layers, the resistance of the link is reduced by transforming the insulating amorphous silicon into conducting polysilicon. This causes a closed or conductive link to be formed between the two metal layers. In the programming of the vROM, current is actively pumped to the link; and a current measurement or check is made prior to the application of the programming voltage to determine whether the link already has been programmed. Immediately following the application of the programming voltage, the current through the link again is checked to determine proper programming of the link.

Abstract: Programming connections convert a partially fabricated six transistor SRAM cell to a ROM cell while avoiding parasitic devices and electrical overstress sensitivity but providing an active pull-up device for the bit line that is to be driven high.

Abstract: A read only memory includes a memory cell provided at an intersection between a word line and a bit line, and a plurality of reference potential transmission lines each receiving a reference potential determined in accordance with an externally applied potential designating signal. The memory cell includes a transistor element having a gate coupled to a word line, a drain coupled to a bit line and a source which is coupled to one of the reference potential transmission lines or is held in an open state. Stored data in the memory cell is changed by switching the potentials of the reference potential transmission lines. This enables storing of different data bits in one memory cell.

Abstract: In a mask ROM, for each of the memory cell groups, a load circuit connected to data lines for the respective memory cell group, a sense amplifier, and a switching circuit are provided. The switching circuit selectively connects one of the data lines which are simultaneously selected, to the sense amplifier. A data line for a dummy memory cell is also connected to the sense amplifier.

Abstract: A mask ROM having a plurality of memory cell blocks, each composed of a main bit line, a ground line, and a plurality of memory cells for storing information. The mask ROM also includes a sense amplifier for reading the information stored in the memory cells via the main bit line. The mask ROM has a plurality of first block selecting means for selecting a memory cell block connected to the main bit line from a plurality of the memory cell blocks and a plurality of second block selecting means for selecting a memory cell block connected to the ground line from a plurality of the memory cell blocks. The first and second block selecting means are arranged alternately, with the memory cell block sandwiched therebetween.

Abstract: A MOS semiconductor memory device comprises a semiconductor substrate of a first conductive type; impurity diffused regions of a second conductive type different from the first conductive type formed into a plurality of spaced columns extending in a first direction on one surface of the semiconductor substrate and having functions of bit lines; a plurality of columns of element isolation insulating films formed on the impurity diffused regions of the second conductive type, with active regions formed therebetween; a plurality of MOS transistors formed in the active regions aligned in each of a plurality of rows extending in a second direction substantially perpendicular to the first direction, each MOS transistor including a gate formed on a part of the active region with a gate insulating film therebetween and source and drain formed in the impurity diffused regions of the second conductive type; and word lines each connected electrically to the gates of the MOS transistors aligned in each of the rows and ex

Abstract: A semiconductor device includes memory cells each of which include a plurality of groups of an anti-fuse and a transistor connected in series; a capacitor including first and second electrodes, with the first electrode connected to a bit line of the memory cell; a first switch connected between the bit line and a power source; a second switch connected between the power source and the second electrode of the capacitor; and a third switch connected between the second electrode of the capacitor and a ground. A specific memory cell is selected out of the memory cells, and a superposed supply voltage is applied through the capacitor to the anti-fuse of the specific memory by turning on and/or off the first through third switches, so that a storage of information in the memory cell can be performed.

Abstract: A read-only memory includes columns of memory cell arrays, a plurality of banks formed by dividing each column of the memory cell arrays along the columns, sub-bit lines disposed between adjacent banks situated along the rows and connected to a transistor of each memory cell, and main-bit lines disposed between every two other columns of the memory cell arrays and extending along the columns, wherein the sub-bit lines are divided into sets of three sub-bit lines connected to a pair of adjacent banks situated along the rows, and one end of each center sub-bit line being connected to a first main-bit line through a first selector transistor, the first main-bit line passing through one side of the set to which the center bit-line belongs, and the other end of the sub-bit line being connected to a second main-bit line through a second selector transistor, the second main-bit line passing through the other side of the set to which the center sub-bit line belongs, the two outer sub-bit lines being directly connecte

Abstract: A non-volatile programmable memory having:a plurality of unit cells disposed therein, each of said unit cells including an anti-fuse that can write in data by electrically breaking down an insulating film, a select transistor individually connected to said anti-fuse, and a wiring connected to each anti-fuse; andan auxiliary transistor connected between mutually adjacent unit cells, said auxiliary transistor having a source region and a drain region respectively connected between said anti-fuse and said select transistor together incorporated in mutually adjacent unit cells.

Abstract: A non-volatile memory cell includes heavily doped source 12 and drain 14 regions separated by a channel region 16. The source 12 and drain 14 are isolated from floating gate 18 and control gate 22 by thick oxide 36. A floating gate 18 is formed over and insulated from a portion of said channel region 16 adjacent to the source 12 and a control gate 22 is formed over and insulated from the floating gate 18 and the remaining portion of the channel region 16. The cell is programmed by applying a nearly reference voltage V.sub.s to the source region 12 and applying a drain voltage V.sub.D to the drain region 14. A gate voltage V.sub.G is applied to the control gate 22 such that an inversion region 15 is formed in the remaining portion of said channel region 16 such that the floating gate 18 is charged up by hot electron injection on the side away from the source junction. The source junction is self aligned to floating gate and is graded for efficient erase. Other key features and methods are also disclosed.

Abstract: A thin-film ROM device includes an array of open circuit and closed-circuit cells (5 to 8) formed from a stack of thin films (12,21,22,23,11) on a glass or other substrate (10). The semiconductor films (21,22,23) may be of hydrogenated amorphous silicon. At least one of the semiconductor films (21,22,23) is removed from some of the closed-circuit cell areas (5,7,8) before depositing the next film. In this way, at least a second type of thin-film diode (MIM, MIN, MIP) is formed having a different conduction characteristic to that of a first type (NIP), so increasing the information content of the ROM array. A lower semiconductor film (23) can be readily etched away from the lower electrode film (11) by a selective etching treatment in which the electrode film (11) acts as an etch stop. By monitoring emissions during plasma etching, an upper semiconductor film (21 or 22) can be removed from a lower semiconductor film (22 or 23).

Abstract: A semiconductor device includes memory cells each of which include a plurality of groups of an anti-fuse and a transistor connected in series; a capacitor including first and second electrodes, with the first electrode connected to a bit line of the memory cell; a first switch connected between the bit line and a power source; a second switch connected between the power source and the second electrode of the capacitor; and a third switch connected between the second electrode of the capacitor and a ground. A specific memory cell is selected out of the memory cells, and a superposed supply voltage is applied through the capacitor to the anti-fuse of the specific memory by turning on and/or off the first through third switches, so that a storage of information in the memory cell can be performed.

Abstract: A manufacturing method of a mask-ROM of two-layered gate electrode structure is provided. With this method, a cell transistor having a first-layered gate is converted into the depletion type according to data to be stored in the following manner. That is, a first conductive layer is insulatively formed over a semiconductor substrate of a first conductivity type, a silicon nitride film is formed on the first conductive layer, a polysilicon film is formed on the silicon nitride film, the polysilicon film is patterned and then altered into a silicon oxide film so as to increase its volume, and the silicon nitride film is patterned with the silicon oxide film used as a mask to form windows for permitting impurity to be doped therethrough. Then, impurity for converting cell transistors into the depletion type according to data to be stored is doped from the windows into the substrate through the first conductive layer.

Abstract: A selectively definable semiconductor device is provided. In one form, a composite gate array includes a plurality of logic dedicated general purpose cell regions and a plurality of function dedicated cell regions each of which is disposed between the two corresponding ones of the plurality of logic dedicated general purpose cell regions, whereby each of the cell regions may be used as an interconnection region selectively. In another form, a semiconductor memory device which may be selectively defined as a ROM or a RAM by a metalization process is provided.

Abstract: An electrically programmable element is fabricated in a P-N junction isolated region of a semiconductor body by first extending the depth of the region in the body by introducing dopants through the region into the body by ion implantation or by diffusion and drive-in, and thereafter forming an amorphotized layer in the first region overlying the extended portion. The increased depth of the first region provided by the second region prevents damage to the P-N junction between the semiconductor body and the first region during formation of the amorphotized layer.

Abstract: A semiconductor memory device using a junction short type programmable element comprises an epitaxial layer formed on a semiconductor substrate, the epitaxial layer having an opposite conductive type to that of the semiconductor substrate, the epitaxial layer being a collector region; a base region having the same conductive type as the substrate formed in the epitaxial layer; a first emitter region having an opposite conductive type to that of the base region, formed in the base region; an insulating isolation region, formed in said epitaxial layer and around the base region; a second emitter region having a higher impurity concentration than that of the first emitter region and the same conductive type as the of the first emitter region, formed in the first emitter region in such a manner that the second emitter region penetrate the first emitter region upward and downward and extends to the interior of the base region (14) so that a writing current flows concentratedly at the second emitter region.

Abstract: A ROM device includes a plurality of memory cells each storing one of three states, a cell voltage generating circuit for providing a cell voltage corresponding to the state stored in a selected one of the memory cells, and a reference cell for providing a reference voltage which is substantially the same as the cell voltage provided by a memory cell storing an intermediate state of the three states. The ROM also includes a comparator circuit for generating a logical output signal based on the result of a comparison between the cell voltage and the reference voltage.

Abstract: In a junction-shorting type PROM, including transistors, a highly doped region having the same conductivity type as a base is provided between a pair of memory cells. This region is a base contact region which commonly connects paired bases at a surface terminal connected to a word line. The base contact region also extends into the substrate, which is a collector, and prevents minority carries in each of the paired bases from diffusing into an adjacent base, and thus, prevents influence between the paired memory cells. The base contact region may be isolated from emitter regions by a narrow groove filled with insulation material. The narrow groove is deeper than the emitter regions but shallower than the substrate. A memory cell block composed of the paired cells and the base contact region is isolated at its circumference by the narrow groove.

Abstract: A microprocessor controlled configurable logic circuit achieves versatility by including a configurable combinational logic element, a configurable storage circuit, a configurable status buffer, and a configurable output select logic. The input signals to the configurable combinational logic element are input signals to the configurable logic circuit and feedback signals from the storage circuit. The storage circuit may be configured to operate as a D flip-flop with or without set and reset inputs, or as an edge detector. In conjunction with the combinational logic element, the storage circuit may also operate as a stage of a shift register or counter. The output select logic selects output from among the output signals of the combinational logic element and the storage circuit. The configurable status buffer may be configured to provide status information on selected important internal signals of the configurable logic circuit.

Abstract: An electrically programmable logic array (10) for binary signals having signal inputs A.sub.0 -A.sub.x) and signal outputs Q.sub.0 -Q.sub.i) comprises two row lines (a.sub.0,a.sub.0' -a.sub.x, a.sub.x') for each signal input. The signal applied to the signal input is generatable at the one row line in non-negated form and at the other row line in negated form. For each signal output a column line (q.sub.0 -q.sub.i) is provided.In the non-programmable state between each row line and each column line there is an electrically conductive connection interruptable for the purpose of programming. Inserted into the connection between the signal inputs and each associated row line is a controllable switching member (S.sub.0,S.sub.0',-S.sub.x, S.sub.x') which is controllable by a control signal applied thereto in such a manner that its output signal changes with the signal applied to the associated signal input or irrespective of said signal always retains a predetermined signal value.

Abstract: A programmable matrix has improved programming circuitry which allows the matrix to be programmed without raising the output terminals or power supply to higher than normal voltage levels. The circuitry includes a bidirectional output buffer and a multi-purpose input pin. The output buffer is provided with a control input and at least one buffer output. A switching device in the buffer provides a path to ground for programming current when a programming enable signal is applied to the control input and a concurrent operating level voltage pulse is applied to a selected buffer output. Programming current may be supplied via a dedicated input pin, but is preferably supplied via the multi-purpose input pin. A higher than normal operating voltage signal applied to the multi-purpose input pin acts to produce the programming enable signal which is subsequently applied to the buffer control input.

Abstract: A semiconductor PROM contains a group of PROM cells (12) each consisting of a pair of opposing diodes oriented vertically with their common intermediate region (22 and 24) fully adjoining a recessed oxide insulating region (16). The PN junction (30) of the upper diode of each pair lies in non-monocrystalline semiconductor material. A composite buried layer consisting of buried regions (32) which adjoin the insulating region below the lower cell regions (20) and a buried web (44) which laterally surrounds each buried region is employed to improve programming efficiency as well as provide intermediate electrical connections.

Abstract: A configurable logic circuit achieves versatility by including a configurable combinational logic element, a configurable storage circuit, and a configurable output select logic. The input signals to the configurable combinational logic element are input signals to the configurable logic circuit and feedback signals from the storage circuit. The storage circuit may be configured to operate as a D flip flop with or without set and reset inputs, an RS latch, a transparent latch with or without set and reset inputs, or as an edge detector. In conjunction with the combinational logic element, the storage circuit may also operate as a stage of a shift register or counter. The output select logic selects output signals from among the output signals of the combinational logic element and the storage circuit.

Abstract: A programmable logic array chip is provided with an auxiliary grid pattern of conductive paths. Connecting elements can be selectively activated to connect certain ones of the auxiliary paths to the normal grid pattern paths which are connected to functional elements. In such manner, it is possible to provide a logic array chip that has increased flexibility in terms of user programmable functions.

Abstract: A programmable cell for use in programmable electronic arrays such as PROM devices, logic arrays, gate arrays and die interconnect arrays. The cells have a highly non-conductive state settable and substantially non-resettable into a highly conductive state. The cells have a resistance of 10,000 ohms or more in the non-conductive state which are settable into the conductive state by a threshold voltage of 20 volts or less, a current of 25 milliamps or less, for 1000 microseconds or less. The cells in the conductive state have a resistance of 500 ohms or less. The cells have a maximum permittable processing temperature of 200.degree. centigrade or more and a storage temperature of 175.degree. centigrade or more. The cells can be formed from chalcogenide elements, such as germanium tellurium and selenium or combination thereof. The cells also can be formed from tetrahedral elements, such as silicon, germanium and carbon or combinations thereof.

Abstract: In fabricating a PROM cell, an electrical isolation mechanism (44 and 32) is formed in a semiconductive body to separate islands of an upper zone (36) of first type conductivity (N) in the body. A semiconductor impurity is introduced into one of the islands to produce a region (48) of opposite type conductivity (P) that forms a PN junction laterally bounded by the island's side boundaries. A highly resistive amorphous semiconductive layer (58) which is irreversibly switchable to a low resistive state is deposited above the region in such a manner as to be electrically coupled to the region. A path of first type conductivity extending from the PN junction through another of the islands to its upper surface is created in the body to complete the basic cell.

Abstract: In fabricating a PROM cell, an electrical isolation mechanism (44 and 32) is formed in a semiconductive body to separate islands of an upper zone (36) of first type conductivity (N) in the body. A semiconductor is introduced into one of the islands to produce a region (48) of opposite type conductivity (P) that forms a PN junction with adjacent semiconductive material of the island. Ions are implanted to convert a surface layer (60) of the region into a highly resistive amorphous form which is irreversibly switchable to a low resistance state. A path of first type conductivity extending from the PN junction through another of the islands to its upper surface is created in the body to complete the basic cell.

Abstract: A method of making an electrically-programmable memory array in which the memory elements are capacitor devices formed in anisotropically etched V-grooves, providing enhanced dielectric breakdown at the apex of the groove. After breakdown, a memory element exhibits a low resistance to a grounded substrate. The method includes forming access transistors in series with the memory elements, and polycrystalline silicon, deposited to form control gates of the access transistors, also forms address lines. Oxide is formed in the V-groove thinner than the gate oxide thickness formed for the access transistor, providing a lower programming voltage. These factors provide a very small, high speed device.

Abstract: A film of titanitum-tungsten nitride is used to provide the dual function of a fuse link between a semiconductive device and an interconnect line in a memory array and of a barrier metal between another metal and a semiconductor region.

Abstract: A ratioless semiconductor read only memory circuit comprises a plurality of insulated gate field-effect transistors being arranged in the form of a matrix consisting of columns and columns, bit lines of the rows of the transistors connected in parallel a sampling transistor connected in series to each of the rows of the transistors and each of the bit lines, and a row selection circuit connected to the respective bit lines for selecting one of the bit lines. The transistors of said array corresponding to individual bits are of the enhancement type or the depletion type depending on desired logic content.

Abstract: The invention relates to non-volatile electrically erasable and reprogrammable memories produced by CMOS technology.According to the invention, each memory element comprises only a single p-channel transistor having a polycrystalline silicon floating gate capacitively coupled to a control electrode. The thicknesses of injection oxide and gate oxide are such that the element can be programmed by avalanche of the drain-substrate junction and erased by field emission of electrons from the floating gate towards the substrate.All the voltages required can be generated on the circuit of the memory from a battery voltage of 1.5 volts.

Abstract: An integrated circuit provided with at least one field-programmable element matrix which is reduced in size and improved in an electrical characteristics is disclosed. The circuit is characterized in that the matrix is physically divided into at least two separate parts, at least a part of a logic circuit for applying a logic input to the matrix or for receiving a logic output from the matrix in a read mode is disposed outside of the separate parts of the matrix, and at least a part of a selection circuit for writing or programming the matrix is disposed between the two divided parts of the matrix.

Abstract: The present invention is directed to a read only memory, wherein the preferred embodiment provides an analog read only memory using charge coupled devices. Fixed but selectable charge packets are used to charge elements in a charge coupled device array; where selectable charging may be provided by selecting resistor values, selecting capacitor values, selectable masking of photo detectors, and other such methods. The accumulated fixed packets of charge are then shifted with a charge coupled device register to provide sequential analog signal outputs. Use of an analog read only memory permits hybrid signal processing such as for voice response. Use of a serial output simplifies the accessing and reduces accessing electronics by eliminating the more complex random access arrangements.

Abstract: An electric current regulating junction that can be electrically activated to a low resistance state in which it is capable of passing a relatively low reading current. The junction is capable of being activated electrically so as to be switched between low resistance and relatively high resistance states and vice versa. To switch from the low resistance to the high resistance state, one may apply relatively low currents (at least 10 times the magnitude of the reading current) in the form of a current-limited pulse, the pulse being regulated so that it will decay rapidly at the end. The junction comprises a normally insulative, electrically activatable composition having an electrical resistance greater than 10.sup.8 ohms through a layer 0.1-2,540 microns thick.

Abstract: A buffer circuit operable with high speed is disclosed. The circuit comprises an input node, an amplifying means having an input coupled to the input node, a first power source, a second power source, a first transistor coupled between the first potential source and the input node, a second transistor coupled between the input node and the second power source, and means responsive to the output of the amplifying means for respectively providing a first signal and a second signal complementary to the first signal to the gates of the first and second transistors so as to restrict a potential amplitude at the input mode.

Abstract: An electrically programmable memory array is made by a process in which the memory elements are capacitor devices formed in anisotropically etched V-grooves to provide enhanced dielectric breakdown at the apex of the groove. After breakdown, a cell exhibits a low resistance to a grounded substrate. Access transistors in series with the memory elements have control gates which also form address lines. The oxide thickness in the V-groove may be thinner than the gate oxide thickness for the access transistor providing a lower programming voltage. These factors provide a very small high speed device.

Abstract: There is provided a read-only memory having a plurality of storage locations wherein more than one binary digit can be stored. The ROM employs field effect transistors having various gate sizes so that the current through the field effect transistors can be controlled by the gain of the transistor. The different levels of current through the different storage locations provide more than two distinct states for each storage location.

Abstract: A thin film programmable read-only memory is provided which comprises an X-Y matrix of conductors, the cross points of which are connected together by a switch element comprising a current-controlled negative differential resistance (CNDR) device in series with a semiconductor fuse. At low bias levels corresponding to read signals, the element behaves as a non-linear resistance. At large bias levels corresponding to write signals, the element will be driven to its negative differential resistance characteristic, the switching element becoming a permanent open circuit when the fuse blows. The symmetrical switching characteristics of the CNDR device allows the function of the X conductors (input or address lines) and Y conductors (output or word lines) to be transposed in that the address information can be applied to the Y lines, the output appearing at the X lines.In an alternate embodiment, a threshold switching (TS) device is utilized in place of the CNDR device.

Abstract: A read-only-memory is provided on a semiconductor chip having a reduced number of power supply lines. The memory has a plurality of storage cells arranged in an array. Vertical lines define columns of the memory. Every other vertical line is coupled to a first node. The first node is controllably coupled to a first voltage potential to controllably precharge the first node. The vertical lines not connected to the first node are connected to an output node. P channel field effect transistors are used to couple the vertical lines to the first node and to the output node. A plurality of N-channel field effect transistors controllably couple the vertical lines to a second voltage potential. A vertical line on one side of the column of memory cells is used to provide a precharge voltage to the cell while a vertical line on the other side of the column of memory cells is used to conduct stored information from the cell to the output node.

Abstract: Binary information is stored in a semiconductor archival memory medium by formation of a region of an alloy, of the semiconductor material and a non-doping material, at each of a plurality of potential memory sites at which a first binary value of information is to be stored, with the remaining data sites being devoid of the alloyed region to store the remaining value of binary data. Methods for writing the formation of the alloyed region, and reading the information value stored at each memory site, are also disclosed.

Abstract: In an integrated circuit, a semiconductor body having a surface, spaced semiconductor circuits formed in the body, intercoupling means formed in the body adjacent each of said circuits, and connected to said circuits. A plurality of conductive paths are formed between said intercoupling means and carried by the body. Each intercoupling means includes a plurality of semiconductor regions formed in the semiconductor body, said regions in combination capable of assuming a first low impedance condition and a second high impedance condition to thereby selectively couple each of said circuits to selected conductive paths or decouple each of said circuits from said conductive paths. In a specific embodiment of the invention a massive monolithic integrated circuit is configured using intercoupling means in combination with small scale random access memory semiconductor circuits. A static MOS random access memory having a 2,048 word capacity, with 9 bits/word and an 11 bit address is provided.

Abstract: A detector circuit for MOS/LSI integrated circuit devices comprises a series transistor which has a sense clock applied to its gate and a gated capacitor connected between the gate and a sense node. The sense node and an input node may be precharged to a level at or near the supply. During the sense clock, the input and sense nodes are shunted together by the series transistor. If at the logic level of the supply, the gated capacitor is off and does not affect the circuit; if the input node decays toward the other logic level, the gated capacitor is on and the trailing edge of the sense clock causes the sense node to be switched to a full logic level.

Abstract: A memory plane for an archival, non-volatile mass storage memory has a planar semiconductor diode with each of a plurality of small P-N junction diodes alloyed into the surface of its fabricated layer responsive to a selectively-actuated scanned energy beam at each location corresponding to a first binary value in a planar array of data sites. Formation of a P-N junction is prevented at each of the remaining sites of the planar data array to provide storage of data having the remaining binary value.Several alternative methods for formation of the alloy junction surface diodes are disclosed.

Abstract: A non-volatile archival memory storage media has a planar junction diode structure into which are written a plurality of diode bits permanently formed at or beneath the top surface thereof by selective ion implantation. Each of the plurality of ion implanted regions represents a data bit of a first binary value, with the remaining un-implanted regions of the planar diode representing data bits of the remaining binary value. The permanently stored data is read by inducing a flow of current by recombination phenomena responsive to a scanning electron beam sequentially incident on each of the possible data bit sites of an array of such sites in the planar diode. Wide bandwidth methods for writing the ion implantation sites into the planar diode media are disclosed.