Abstract: A memory system including a memory array with redundant wordlines is disclosed. The memory system includes a memory wordline tester that determines if any of the wordlines exhibits a defect. The memory system also includes decoder redundancy logic that efficiently couples to wordline shift logic using a reduced number of control signal lines therebetween. The shift logic shifts defective wordlines to upstream wordlines in the array to bypass the defective wordlines.

Abstract: A system and method for generating random noise for use in testing electronic devices comprises a first random pattern generator circuit for generating first sets of random bit pattern signals; one or more delay devices each receiving a trigger input signal and a random bit pattern signal set for generating in response a respective delay output signal, each delay output signal being delayed in time with respect to a respective trigger signal, a delay time being determined by the bit pattern set received; and, an oscillator circuit device associated with a respective one or more delay devices for receiving a respective delay output signal therefrom and generating a respective oscillating signal, each oscillator signal generated being used to generate artificial random noise for emulating a real noise environment in an electronic device.

Abstract: A system and method for generating random noise for use in testing electronic devices comprises a first random pattern generator circuit for generating first sets of random bit pattern signals; one or more delay devices each receiving a trigger input signal and a random bit pattern signal set for generating in response a respective delay output signal, each delay output signal being delayed in time with respect to a respective trigger signal, a delay time being determined by the bit pattern set received; and, an oscillator circuit device associated with a respective one or more delay devices for receiving a respective delay output signal therefrom and generating a respective oscillating signal, each oscillator signal generated being used to generate artificial random noise for emulating a real noise environment in an electronic device.

Abstract: An apparatus for performing ADD and ROTATE as a single instruction within a processor is disclosed. In accordance with a preferred embodiment of the present invention, the apparatus comprises an adder and a rotator. The adder is utilized for adding a first number to a second number in a multiple stages to yield a carry-out and a sum output. During each of these stages, the adder produces a group generate value and a group propagate value. The rotator is utilized for rotating the group propagate value and the group generate value at each of the stages before the yielding of the carry-out and the sum output. As such, both ADD and ROTATE instructions can be completed within a single processor cycle.

Abstract: A zero-stopping incrementer operates on the recognition that half of all digital values that require incrementing will be even numbers; that is, the least significant bit (LSB) is a binary "0". Incrementing such a number merely requires changing the LSB from a binary "0" to a binary "1". For odd numbers (i.e., those where the LSB is a binary "1"), the zero-stopping incrementer searches for the first binary "0" beginning with the LSB. Once found, that binary "0" is changed to a binary "1" and all the binary "1s" preceding it are changed to binary "0s". No change is required to the higher order bits following the first binary "0". This operation is very fast, the worst case being the case when all the binary bits of the number to be incremented are "1s". Nevertheless, the process is significantly increased, especially for 64-bit numbers which are processed by modern superscalar microprocessors.

Abstract: Multiple reads are made from an array of single-read port memory cells. An array of single-read port memory cells is provided with "steering" devices located between a column of cells and the output drivers for the array. The steering devices are controlled by the read pointers such that the steering signal for a given output configuration is active only when read pointers for that output configuration are active. To complete the function, the read pointers are fed to OR gates, one per row, so that a given pointer will activate the read port of a plurality of consecutive memory cells. The read pointers represent the decoded read address and only one is active at a time.

Abstract: Sequentially terminated write enable pulses applied to respective input ports of a multi-port memory cell is effective to establish a priority among those input ports and provide unconditionally unambiguous writing to a memory cell when write operations are concurrently attempted at two or more ports of that cell, as may be encountered during rigorous testing procedures. Memory structure, particularly that of the input port circuits, is simplified and operational speed is enhanced since signal propagation through a comparator or logic circuit is avoided. Time required for testing of large memory arrays is also significantly reduced.

Abstract: A device for controlling the voltage across an NMOS pull-up transistor including a source node which may be exposed to a variable voltage. The device further includes a gate node which may be exposed to a variable voltage. A control portion regulates the voltage applied to the gate node, wherein a differential in voltage between the source node and the gate node is limited to a desired level.

Abstract: A voltage regulator is provided for controlling an on-chip voltage generator which produces a boost voltage across a charge reservoir for supply to one input of a plurality of word line drivers in a memory array. The regulator is configured such that the charge reservoir voltage will track the power supply voltage and the difference between the power supply voltage and the charge reservoir voltage will be maintained substantially constant over a predefined power supply range. The voltage regulator includes a bandgap reference generator, a first differential circuit for producing a transition voltage from the reference voltage and the power supply voltage, a first transistor for comparing the power supply voltage with the boost voltage, a second transistor for comparing the transition voltage with the reference voltage and a latching comparator for equating the signal outputs from the first and second transistors so as to define a control signal for the on-chip voltage generator.

Abstract: A flash EEPROM is produced comprising multiple MOS cells. In each cell, programming and erasing are performed through tunneling from the write gate to the floating gate and by tunneling from the floating gate to the erase gate, respectively. The directional dielectric employed is a multilayered structured (MLS) oxide, where thin oxide and thin polycrystalline silicon form alternating layers. The layering is asymmetric: that is, either the uppermost or bottommost layer is thicker than the other layers. As a result of this structure, the oxide exhibits directionality, that is, the tunneling is easier in one direction than the reverse direction, and significantly enhances the tunneling phenomena (tunneling current can be observed at as low as 4.7 V). In addition, the MLS oxide can be fabricated having different dielectric constants.

Abstract: A pull-down circuit for a TTL compatible data output buffer uses NMOS devices. The pull-down circuit comprising two NMOS stages. Namely, a diode configuration stage where the gate and drain electrodes are shorted together during pull-down and a common-source stage. Both PMOS and NMOS devices are used for shorting the gate and drain electrodes.

Abstract: A high density substrate plate DRAM cell memory device and process are described in which a buried well region is formed adjacent to deep trench capacitors such that the substrate region of DRAM transfer FETs can be electrically isolated from other FETs on a semiconductor substrate. The buried region is partially formed by ion implantation and diffusion to intersect the walls of the deep trenches.

Abstract: A voltage regulator is provided for controlling an on-chip voltage generator which produces a boost voltage across a charge reservoir for supply to one input of a plurality of word line drivers in a memory array. The regulator is configured such that the charge reservoir voltage will track the power supply voltage and the difference between the power supply voltage and the charge reservoir voltage will be maintained substantially constant over a predefined power supply range. The voltage regulator includes a bandgap reference generator, a first differential circuit for producing a transition voltage from the reference voltage and the power supply voltage, a first transistor for comparing the power supply voltage with the boost voltage, a second transistor for comparing the transition voltage with the reference voltage and a latching comparator for equating the signal outputs from the first and second transistors so as to define a control signal for the on-chip voltage generator.

Abstract: High speed, low power signal switching logic implementable in bipolar or BiCMOS technology is described. Signal switching is between a first prescribed state and a second prescribed state and is accomplished using a conventional active signal pull-up circuit in combination with a novel self-biased, feedback-controlled active signal pull-down circuit. The active signal pull-down circuit is driven by a feedback signal obtained from the active pull-up circuitry such that only a single input connection to the signal switching circuit is required. Preferably, the active signal pull-up circuit comprises an emitter follower coupled transistor and the drive signal for the active signal pull-down circuit is taken from the collector thereof via a dc-coupling level shifter. Various signal switching circuit embodiments are described.

Abstract: A sensing technique uses a variable precharge voltage sensing with a single bitline swing in a DRAM cell or array of DRAM cells so that the power dissipation is reduced. The bitline precharge voltage varies from one RAS cycle to the next RAS cycle depending upon the level of the data in the accessed cells. Such an arrangement eliminates the need for a reference voltage generator since the precharge voltage is not the same voltage for each RAS cycle.

Abstract: A folded bitline DRAM cell is described which includes a trench capacitor and a planar-configured access transistor. The access transistor is stacked over the capacitor and has a first terminal connected thereto. The access transistor includes a planar-oriented gate. A first wordline has a minor surface in contact with the gate and a major surface that is oriented orthogonally to the gate. An insulating pedestal is positioned adjacent the gate and a passing wordline is positioned on the pedestal, the passing wordline having a major surface parallel to the first wordline. In another embodiment, the folded bitline DRAM cell includes a vertically oriented access transistor having one terminal formed on the upper extent of a contact to the trench capacitor, to provide optimum electrical connection thereto.

Abstract: A flash EEPROM is produced comprising multiple MOS cells. In each cell, programming and erasing are performed through tunneling from the write gate to the floating gate and by tunneling from the floating gate to the erase gate, respectively. The directional dielectric employed is a multilayered structured (MLS) oxide, where thin oxide and thin polycrystalline silicon form alternating layers. The layering is asymmetric: that is, either the uppermost or bottommost layer is thicker than the other layers. As a result of this structure, the oxide exhibits directionality, that is, the tunneling is easier in one direction than the reverse direction, and significantly enhances the tunneling phenomena (tunneling current can be observed at as low as 4.7 V). In addition, the MLS oxide can be fabricated having different dielectric constants.

Abstract: A semiconductor memory device and operational method having reduced well noise are provided. The memory device includes a plurality of memory cells arranged in rows and columns within an array well and addressable by a plurality of word lines and bit lines. The array well is biased to a desired potential and a sense amplifier is employed to read bit line states during a predefined bit line signal development period. Array well biasing is removed during at least a portion of this signal development, so that the well potential floats (ideally remaining stable) as signals are being developed on the bit lines. This temporary, floating well technique is particularly important for open bit line architectures.

Abstract: Disclosed is a Dynamic Random Access Memory (DRAM) cell which includes a storage capacitor disposed in a trench formed in a semiconductor substrate and an access transistor disposed in a well which is opposite in conductivity type to that of the substrate and a buried oxide collar which surrounds an upper portion of the trench.

Abstract: A new interdigitated folded bit line (IFBL) architecture for a future generation high density semiconductor memory design is disclosed. In the architecture, the basic cross-point memory cells are organized orthogonally in rows and columns to form an array matrix. The bit lines run in a row direction while the word lines run in a column direction. Transfer transistors are designed to be shared with the same drain junction and the same bit line contact in order to save area. A choice of at least two described embodiments are provided. In one embodiment, referred to as the offset bit line structure, the bit lines are constructed by using two layers of interconnection lines to connect the interdigitated cells associated to it. By connecting the bit line contacts and with two different interconnecting layers and in an alternating row order, the true and complement bit lines and will run parallel to both sides of the memory array.