International Business Machines Corporation

Emagin Corporation

Other

Shashi D Malaviya

George R Goth

Harsaran S Bhatia

Ingrid E Magdo

Gurumakonda R Srinivasan

Dominic Joseph Schepis

John S Lechaton

Olivier F Prache

Harry J Jones

Sudipta Kumar Ray

Mario John Interrante

Daniel Peter Morris

Herbert I Stoller

Chakrapani G Jambotkar

Mario E Ecker

Suresh D Kadakia

Mark Harrison McLeod

Madhukar B Vora

William T Wilson

A circuit is disclosed for driving an OLED in a graphics display. The circuit employs a current source operating in a switched mode. The output of the current source is connected to a terminal of the OLED. The current source is responsive to a combination of a selectively set cyclical voltage signal and a cyclical variable amplitude voltage signal. The current source, when switched on, is designed and optimized to supply the OLED with the amount of current necessary for the OLED to achieve maximum luminance. When switched off, the current source blocks the supply of current to the OLED, providing a uniform black level for an OLED display. The apparent luminance of the OLED is controlled by modulating the pulse width of the current supplied to the OLED, thus varying the length of time during which current is supplied to the OLED. By using a switched mode of operation at the current source, the circuit of the present invention is able to employ a larger range of voltages to control the luminance values in a current-driven OLED display.

Gray scale pixel driver for electronic display and method of operation therefor

Circuits for sequentially addressing memory locations in time with pulses received from a clock are disclosed. The circuits may provide a positive voltage output signal at successive output nodes associated with corresponding stages in the circuit responsive to the application of a clock signal to the circuit stages. The circuit may comprise at least first and second stages wherein said first stage comprises means for providing a positive voltage signal at a first output node in the first stage in response to application of a first positive clock pulse to the first stage, and wherein said second stage comprises means for providing a positive voltage signal at a second output node in the second stage in response to application of a second positive clock pulse to the second stage. Addressing of memory locations that contain pixel information for a video display is one particular application in which sequential addressing may be required. Sequential addressing is useful in video applications because it permits sequential selection of the pixel rows and columns that make up the display screen. Sequential scanning of the memory locations for screen information can be carried out in conjunction with the scanning of an electron source across the screen of the display.

Method and apparatus for sequential memory addressing

A direct distribution wiring system is provided which facilitates the effecting of repair or engineering change in a Multi-chip module (MCM) while eliminating the need for redistribution and/or buried connections between IC attachment pads and engineering change pads, thus eliminating the need for patterned conductor layers corresponding to such functions. The operation of the MCM is improved by the wiring system allowing the reduction of lumped capacitances by disconnection of defective conductors, accomplished by providing severable connectors in a direct distribution structure, as well as the elimination of redistribution wiring layers and increased IC density on the MCM. Full potential fault coverage as well as full discretion in reversible engineering changes is provided by forming all elements of the wiring system on the surface of the device.

Direct distribution repair and engineering change system

A method of integrated circuit fabrication and the resulting integrated circuit wherein areas of recessed oxide isolation surround active device regions and the bird's head and bird's beak formed during formation of the recessed oxide regions is eliminated by forming a deep dielectric isolation trench directly over the bird's head. A very thin epitaxial layer can be provided over the active device regions of the integrated circuit. Preferably, the thin epitaxial layer is selectively grown only over active device regions. Also, in later manufacturing steps, metal is deposited in direct registration with contact areas.

Semiconductor device and process

Disclosed is a submicron wide single crystal silicon structure protruding from a monolithic silicon body. This three-dimensional structure includes lower section of a first (N) conductivity type and an upper section of a second (P) conductivity type. The upper section consisting of narrow top and bottom portions separated by a relatively wide middle portion, constitutes the silicon material from which various active or passive integrated circuit devices may be fabricated. For example, in the case of an NPN transistor, the central region of the middle portion constitutes the base region, the emitter and collector being embedded in the two outer side regions thereof in a mutually facing relationship. Electrical contacts to the elements of the IC device are established on the top and/or sides of the protruding structure. Owing to its free-standing self-isolated characteristic, dielectric isolation of the IC device is not necessary. Alternatively, total dielectric isolation of the IC may be achieved by utilizing a dielectric material for the bottom of the protrusion.

Stud-defined integrated circuit structure

A method of forming on a substrate a pattern of structures having a thickness on the order of one micron or less. A first insulating layer is formed on a major surface of a substrate, for example, a silicon body. A polycrystalline silicon layer is formed thereover and openings are formed therein by reactive ion etching to provide substantially horizontal surfaces and substantially vertical sidewalls. The vertical sidewalls of the openings are formed at the desired locations of the narrow dimensioned structures. A second, conformal insulating layer is then formed followed by a reactive ion etching step which substantially removes the horizontal portions of the second insulating layer. The remaining polycrystalline silicon layer is removed to leave a pattern of self-supporting narrow dimensioned dielectric regions on the major surface of the substrate. The narrow dimensioned dielectric regions can be used as a mask to form narrow structures in the substrate. Alternatively, a self-aligned pattern of metallization can be formed using the narrow dimensioned dielectric regions to provide sub-micron metal-to-metal spacing.

Self-aligned metal process for integrated circuit metallization

A specially designed module and integrated circuit chip therefor which permits the sharing of module EC pads between chip receiver and driver circuits. The chip has a direct normal input line to each receiver circuit therein and a direct normal output line from each driver circuit therein along with signal lines from each of those circuits to various EC pads. The chip further includes a switching and control circuit for switching the receiver circuits and driver circuits between their normal and EC lines to effect an electronic delete function. In a preferred embodiment, a majority of the EC pads are switchably connected via the switching and control circuit to different sets of three adjacent receiver circuits, driver circuits, or a combination thereof. The design permits the use of approximately half the EC pads normally required for a module, while permitting EC connections to be made in most cases to three adjacent receiver or driver circuits simultaneously.

Electronic EC for minimizing EC pads

A new dotting circuit for integrated circuit chips which provides line switching, as well as simultaneous true and complementary outputs, while eliminating the need for the standard collector circuit voltage clamp. This circuit is implemented by the collector dotting of two or more input transistors, the collector dotting of their respective reference transistors, the emitter dotting of one input transistor and a reference transistor to a constant current source, the emitter dotting of the other input transistor and the other reference transistor to a different constant current source, and an inhibit circuit for permitting current to flow to only one of the emitter-dotted circuits in accordance with a logic control signal.

Dotting circuit with inhibit function

Submicron lateral device structures, such as bipolar transistors, Schottky Barrier diodes and resistors, are made using self-aligned fabrication techniques and conventional photolithography. The devices are made using individual submicron silicon protrusions which extend outwardly from and are integral with a silicon pedestal therefor. Both PNP and NPN transistors may be made by diffusing appropriate dopant material into opposing vertical walls of a protrusion so as to form the emitter and collector regions. The protrusions themselves are formed by anisotropically etching the silicon using submicron insulating studs as a mask. The studs are formed using sidewall technology where a vertical sidewall section of as layer of insulating material is residual to a reactive ion etching process employed to remove the layer of insulating material.

Lateral device structures using self-aligned fabrication techniques

An attenuator useful in measuring low level leakage currents is disclosed. The attenuator includes a plurality of current dividers coupled in cascade. Each current divider includes an input and two outputs between which the current entering the input is divided. The current exiting the last divider is significantly attenuated from that entering the attenuator. The attenuator output is coupled to the device under test and to one input of a differential amplifier. A known current is input to the differential amplifier and part is directed to the attenuator input and the other part to a current measuring device. The difference between the known current input to the differential amplifier and that measured is the current input to the attenuator. In the steady state, the current input to the differential amplifier from the current attenuator is about zero. Accordingly, the leakage current is equal to the known current entering the differential amplifier less the measured current divided by m, the attenuation provided by the attenuator.

Current attenuator useful in a very low leakage current measuring device

A high density integrated circuit structure, for example a dynamic memory cell, is described which includes an active/passive device in combination with a capacitor structure. The capacitor structure is of the polysilicon-oxide-silicon type and is formed on the sidewalls of a mesa-shaped and dielectrically isolated region of silicon material resulting from the formation of an isolation trench in the silicon. The trench is filled with a plastic material, such as polyimide. The capacitor is formed by the isolated region of silicon material which functions as the first capacitor plate, a doped polysilicon layer provided on the vertical walls of the mesa serving as the second capacitor plate and a thin dielectric layer interposed between the two plates serving as the capacitor's dielectric. Since the polysilicon is wrapped around the periphery of the mesa as a coating on the vertical sidewalls thereof, it gives rise to a large storage capacitance without an increase in the cell size.

Method of making trench-incorporated monolithic semiconductor capacitor

Submicron lateral device structures, such as bipolar transistors, Schottky Barrier diodes and resistors, are made using self-aligned fabrication techniques and conventional photolithography. The devices are made using individual submicron silicon protrusions which extend outwardly from and are integral with a silicon pedestal therefor. Both PNP and NPN transistors may be made by diffusing approximate dopant materials into opposing vertical walls of a protrusion so as to form the emitter and collector regions. The protrusions themselves are formed by anisotropically etching the silicon using submicron insulating studs as a mask. The studs are formed using sidewall technology where a vertical sidewall section of a layer of insulating material is residual to a reactive ion etching process employed to remove the layer of insulating material.

A fully isolated dielectric structure for isolating regions of monocrystalline silicon from one another and method for making such structure are described. The structure uses a combination of recessed oxide isolation with pairs of parallel, anisotropic etched trenches which are subsequently oxidized and filled to give complete dielectric isolation for regions of monocrystalline silicon. The anisotropic etching preferably etches a buried N+ sublayer under the mnocrystalline silicon region and then the trench structure is thermally oxidized to consume the remaining N+ layer under the monocrystalline region and to fully isolate the monocrystalline silicon region between pairs of such trenches.

Total dielectric isolation for integrated circuits

Fabrication of a submicron wide single crystal silicon structure protruding from a monolithic silicon body. Starting with a single crystal N silicon body having a P region, an insulator stud of submicron width and length dictated by the limits of lithography is formed on the P region. Using the stud as a mask, the P region is etched forming the top narrow portion having the stud width projecting from the silicon body. On the exposed sides of the top portion oxide walls are formed and the etching continued forming the middle portion of a width exceeding that of the top portion. An oxide-nitride wall is established on the exposed sides of the middle portion and, using the resulting structure as a mask, the etching is continued to completely etch through the P region and a substantial portion of the underlying N silicon body thereby forming a free-standing silicon protrusion structure. Thick oxide walls are formed on the just exposed sides of the silicon. Alternatively, the exposed sides of silicon may be completely oxidized to obtain a fully dielectrically isolated silicon protruding structure. To form NPN device from the silicon protrusion structure, the oxide-nitride walls corresponding to the middle portion are removed and N-type dopant is introduced from the thus exposed sides forming the emitter and collector juxtaposed on either side of the central P-type region which functions as the base. Self-aligned metal contacts to the elements of the transistor are established on the top and sides.

Fabrication of stud-defined integrated circuit structure

A self-aligned metal integrated circuit structure is described which achieves self-aligned metal to silicon contacts and sub-micron contact-to-contact and metal-to-metal spacing. The insulation between the contacts and the metal is a pattern of dielectric material having a thickness dimension in the order of a micron or less. The metal and dielectric structure is substantially planar. The method for forming this structure involves providing a silicon body and then forming a first insulating layer on a major surface of the silicon body. A layer of polycrystalline silicon is formed thereover. Openings are made in the polycrystalline silicon layer by reactive ion etching which results in the structure having substantially horizontal surfaces and substantially vertical surfaces. A second insulating layer is then formed on both the substantially horizontal surfaces and substantially vertical surfaces. Reactive ion etching of this second insulating layer substantially removes the horizontal layers and provides a narrow dimensioned dielectric pattern of regions on the major surface of the silicon body. The remaining polycrystalline silicon layer is then removed by etching to leave the narrow dimensioned regions on the major surface of the silicon body. A conductive layer is blanket deposited over the narrow dimensioned regions and areas in between. The surface is planarized, leaving the structure of metal filling the regions between the pattern of dielectric material.

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Fishkill, NY, United States of America

Shashi D Malaviya