International Business Machines Corporation

Jack A Dorler

Joseph M Mosley

Dennis C Banker

Stephen Douglas Weitzel

Walter S Klara

Francesco M Masci

Frank M Masci

Paul David Hendricks

Erich Berndlmaier

Harsaran S Bhatia

Michael O Jenkins

James J Curtin

Allan Harvey Dansky

Santosh Prasad Gaur

Steven John Zier

John S Lechaton

Gurumakonda R Srinivasan

James R Struk

George J Jordy

Adrian Zuckerman

Richard O Seeger

John N Hryckowian

Richard Jay Blumberg

Stephen J Tytran

Tore A Carlson

Bernard T Clark

Kenneth L Leiner

Relatively constant current sources and current mirrors are formed with vertical bipolar transistors operated in the inverse mode. In one embodiment of the invention, an integrated circuit current mirror includes a dual collector vertical NPN bipolar transistor having first and second regions of one conductivity type defining first and second collector regions, respectively, formed within a common third region of opposite conductivity type defining the base of the transistor. The third region is formed within a fourth region defining the emitter of the transistor. The structure of the dual collector vertical transistor is very compact since the two collectors share the same base region which is embedded in a common emitter (inverse collector) pocket. The 'inverse' mode vertical transistor can function as a relatively constant current source with a voltage drop (VCEi) across its collector-to-emitter which is substantially less than that of a bipolar transistor operated in a normal mode. Transistors embodying the invention may be used to provide relatively constant current sources to numerous utilization means, such as logic or analog circuits. Due to the low VCEi of the 'inverse' mode transistor, the resultant circuits can be operated at a lower operating voltage than prior art circuits. This results in a decrease of power dissipation.

Integrated circuit employing inverse transistors

This invention contemplates the provision of a noise immune integrated circuit receiver in which the voltage reference to one side of an emitter-coupled current switch moves in response to the input signal, in a direction opposite the input signal. This provides the gate with a threshold hysteresis, making it immune to noise without requiring a large swing in input signal.

High noise tolerance receiver

CMOSFETs control the power in a bipolar logic gate to regulate its operating speed and hence its delay. In a specific embodiment of the invention, an n-channel CMOSFET controls the constant current through an emitter-coupled current switch, comprised of a pair of bipolar integrated circuit transistors. A p-channel CMOSFET, in series with each collector of the switch pair, establishes the collector voltage so as to maintain constant the output swing of the gate as the power through the gate is varied in order to regulate the gate delay. An error signal, indicative of factors that can cause variations in gate delay and the inverse of the error signal are generated by an on-chip circuit. The error signal is coupled to the n-channel CMOSFET and the inverse of the error signal is coupled to the p-channel CMOSFET. Thus, as the switch current is decreased in order to increase the gate delay, the collector impedance is simultaneously increased so the collector voltage, and hence the gate swing, remains constant. Similarly, when the switch current is increased, the collector impedance is decreased.

BICMOS ECL circuit suitable for delay regulation

A high performance bipolar, field effect transistor (BiFET) logic circuit has minimal power supply requirements, allowing the circuit to be manufactured in higher density devices than current switched emitter follower (CSEF). BiFET logic circuit has a plurality of input lines and first and second output lines. A plurality of FET devices are connected in parallel each having a gate connected to a corresponding one of the input lines. Two bipolar transistors are connected as a differential pair, the parallel connection of said FET devices providing an input to the base of the first bipolar transistor while the base of the second bipolar transistor is supplied with a reference voltage. Output bipolar transistors connected as emitter followers drive the first and second output lines respectively. One of these output bipolar transistors is driven by the first bipolar transistor of the differential pair, while the other of the output bipolar transistors is driven by the second bipolar transistor of the differential pair. By dotting the collectors of the differential pair, as is commonly done in CSEF circuits, additional logic functions are obtained; however, the number of additional logic functions obtained is greater than that obtainable in CSEF circuits. Thus, the BiFET has the additional advantage of providing additional logic function and flexibility as compared with CSEF circuits.

High performance BiFET complementary emitter follower logic circuit

NOR logic performed by a half current switch emitter follower ('HCSEF') circuit utilizing a transistor operated in the inverse active mode as its current source and having logic levels compatible with those of current switch emitter follower ('CSEF') circuitry is combined with a novel reference bias generator that controls the logic low voltage level by controlling the voltage drop across the current source. The NOR.sub.i circuit utilizes less power than CSEF circuits, has a natural threshold equal to the threshold of CSEF circuits to which it is coupled, has a delay skew of approximately 1:1, and maintains minimum signal levels with respect to variations on V.sub.cc. The reference bias generator compensates for temperature, process variables and variations in the NOR.sub.i circuit and in the power supply.

NOR.sub.i circuit/bias generator combination compatible with CSEF

A logic redundancy circuit scheme, comprising a plurality of pairs of logic circuit groups, each logic circuit group in a given pair having a respective logic node and a respective power control line, with each logic circuit group in a given pair generating substantially the same logic function signal on its respective logic node as the other logic circuit group in the given pair generates on its respective logic node. The circuit scheme further includes a plurality of isolation circuits having respective output nodes, with a different isolation circuit connected to each different logic circuit group logic node. These isolation circuits are powered at all times and each operates to provide an output signal on its output node indicative of the signal on the logic node connected thereto, while isolating the connected logic node from nets connected to the isolation circuit output node. The circuit scheme also includes means for electrically connecting together for bidirectional communication the logic nodes for each pair of logic circuit groups, prior to the connection to the isolation circuit associated therewith, and switching means connected to each of the power control lines associated with the plurality of pairs of logic circuit groups for providing power to one and only one logic circuit group in each pair of logic circuit groups. The circuit scheme also includes means for controlling, through the electrically connecting means, the logic state at the isolation circuit output node of the logic circuit group in a given pair of logic circuit groups, which is not powered, to have the same logic state as the isolation circuit output node of the logic circuit group in the given pair of logic circuit groups which is powered by the switching means, so that both isolation circuit output nodes in the pair provide a correct logic signal.

Logic redundancy circuit scheme

A BIFET logic circuit for quickly switching an output line from a high level to a reference level. The BICMOS circuit comprises a push-pull circuit including a first bipolar transistor for driving current into an output line, and a second bipolar transistor for sinking current from the output line; a CFET logic circuit for performing a logic function and including at least one N type FET for providing current to the base of the second bipolar transistor when a set of input lines to the CFET circuit has a first set of predetermined values; and a resistive means for connecting one of the source or drain of the at least one NFET to a power supply to provide a source of base current to the second bipolar transistor, even when the output line drops in voltage. This circuit is especially advantageous for driving low threshold CFET circuits. In a preferred embodiment, the circuit further includes a device for preventing a voltage differential of more than a predetermined amount between the base and emitter of the first bipolar transistor, to thereby ensure proper push-pull operation of the bipolar transistors.

BIFET logic circuit

Disclosed is a Complementary Cascoded Logic (C.sup.2 L) Circuit which performs the AND-INVERT (AI) (or NAND) function. The AND function is implemented with input PNP transistors and the invert function is implemented with a first NPN transistor. An inverted NPN transistor serves as a current source for the first NPN. A first low voltage Schottky diode is serially connected between the emitter of the first NPN transistor and the emitter of the inverted NPN current source transistor. The first Schottky diode precludes, under certain conditions, simultaneous conduction of the first NPN transistor and the inverted transistor. Oppositely poled second and third low voltage Schottky diodes are utilized via an emitter follower output to provide an output voltage swing of V.sub.R .+-.V.sub.F, where V.sub.R is a reference voltage and V.sub.F is the potential drop across a Schottky diode. The low power high speed logic circuit (C.sup.2 L) has particular utility in redundant circuit applications.

Complementary cascoded logic circuit

A process is described which permits the fabrication of very narrow base width bipolar transistors in selected areas of an integrated circuit chip and bipolar transistors of wider base width on other selected areas of the same integrated circuit chip. The ability to selectively vary the transistor characteristics from one region of an integrated circuit chip to another provides a degree of freedom for design of integrated circuits which is valuable. The bipolar transistors on an integrated circuit chip are processed up to the point of emitter formation using conventional techniques. But, prior to the emitter formation, the base area which is to be the emitters of the selected region having the very narrow base transistors is dry etched using reactive ion etching. The existing silicon nitride/silicon dioxide layers with the emitter opening therein are used as the etching mask for this reactive ion etching procedure. Once the etching is completed to the desired depth, the normal processing is resumed to form the emitter and rest of the metallization.

Method and resulting structure for selective multiple base width

Compensation circuit means for inclusion in an off-chip driver circuit is provided to reduce self-induced switching noise in a multi-chip module semiconductor structure. A module section interconnects the chips and the chips have a power supply and power leads respectively. The compensation circuit means, which is coupled across the output transistor circuit of the off-chip driver, may comprise one or more serially connected diodes. The diode (or diodes) may be formed by the base collector junction of a bipolar transistor.

Driver circuitry for reducing on-chip Delta-I noise

A driver circuit for a capacitively loaded line employs the charge storage capacitance of a diode for raising the base of a driver transistor above the circuit power supply voltage level so as to pull up the line to within a transistor base-emitter voltage drop of the power supply voltage level. The driver is easily fabricated in integrated circuit form, as no capacitors, either on or off chip, are required. The driver circuit includes a driver transistor, the collector of which is connected to the power supply and the emitter of which is connected to the line. A switching transistor has an input voltage applied between its base and emitter. A diode is connected between the switching and driver transistors, the anode being connected to the base of the driver transistor, and the cathode being connected to the collector of the switching transistor. In response to a first input signal, the switching transistor turns on, forward biasing the diode and building up a voltage thereon as a result of the diode's charge storage capacitance. In response to a second input signal, the switching transistor turns off, raising the anode to the power supply voltage, and raising the cathode (and the base of the driver transistor connected thereto) to a voltage higher than the power supply voltage. The emitter of the driver transistor (and the line connected thereto) is thus pulled up to a value nominally approaching the power supply voltage, despite the base-emitter voltage drop of the driver transistor.

Diode-transistor active pull up driver

A current controlled gate performing a NOR function utilizes a pair of transistors acting as current mirrors that receive a DC bias through a large resistor. This bias occurs when an input transistor is positive to insure that one of the current mirror transistors will saturate when the input transistors are 'off' and the other will be driven into saturation when either of the input transistors is 'on'. When all inputs are negative, one of the current mirror transistors saturates thereby reducing the current to the input transistors effectively to zero. The saturation results in the collector-base capacitance increasing very rapidly such that the input assumes the characteristics of a common emitter due to the large capacitance existing in the collector of the current mirror transistor. An active push-pull output is produced with a single collector path from input to output.

Transient controlled current switch

An on chip delay regulator circuit which varies the power in logic or array circuits on the chip so as to minimize, or eliminate, chip to chip circuit speed differences caused by power supply variations and/or lot to lot process differences, temperature, etc. The on chip delay regulator accomplishes this by comparing a periodic reference signal to a periodic on chip generated signal which is sensitive to power supply changes, lot to lot process changes, temperature, etc. The comparison creates an error signal which is used to change the power (current or voltage) supplied to the on chip circuits. By changing the circuit power, the circuit speed (gate delay) is increased or decreased as necessary to maintain a relatively constant circuit speed on each chip. For example, a plurality of integrated circuit chips each contain an on chip delay regulator. The on chip delay regulator on each chip of said plurality of integrated circuit chips receives and responds to the same signal (or clock). Each chip provides a discrete on chip generated signal related to the parameters of the chip. The gate delay (or speed) of the circuitry on each chip is determined by its on chip delay regulator under control of the common reference signal (or clock). At least certain of the chips include an AC measurement circuit for comparing the periodicity of said reference signal with the periodicity of said on generated chip signal and cooperating with the delay regulator thereof to provide one of three discrete electrical manifestations.

AC Measurement means for use with power control means for eliminating

An on chip delay regulator circuit which varies the power in logic or array circuits on the chip so as to minimize, or eliminate, chip to chip circuit speed differences caused by power supply variations and/or lot to lot process differences, temperature, etc. The on chip delay regulator accomplishes this by comparing a reference signal to an on chip generated signal which is sensitive to power supply changes, lot to lot process changes, temperature, etc. The comparison creates an error signal which is used to change the power (current or voltage) supplied to the on chip circuits. By changing the circuit power, the circuit speed (gate delay) is increased or decreased as necessary to maintain a relatively constant circuit speed on each chip. For example, a plurality of integrated circuit chips each contain an on chip delay regulator. The on chip delay regulator on each chip of said plurality of integrated circuit chips receives and responds to the same signal (or clock). Each chip provides a discrete on chip generated signal related to the parameters of the chip. The gate delay (or speed) of the circuitry on each chip is determined by its on chip delay regulator under control of the common reference signal (or clock).

Power control means for eliminating circuit to circuit delay differences

Heat is removed from a Large Scale Integrated Circuit semiconductor package via a thermal conductive path including a thermally conductive liquid. The integrated circuit chips are flip chip bonded to a substrate having a printed circuit and raised contact pads serving to interconnect contact areas on the chip. A metal, ceramic (or combination thereof) cover engages the perimeter of the substrate and encloses the chips (or chip). The thermal liquid is contained within the cavity define by the cover and substrate. The chips (or chip) and the flip chip connections are protected from contamination and the deleterious effects of the thermally conductive liquid by a parylene film enveloping same. Additionally, back side bonded (beam lead) integrated circuit chips will have an enhanced heat transfer path by incorporating liquid metal and a protective coating of parylene.

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Wappingers Falls, NY, United States of America

Jack A Dorler