Abstract: The generation of a controlled voltage signal as a buffer control signal for an output driver provides for relatively less delay for a high output enable access for an output buffer. As the output buffer undergoes the transition from a deselected state to a selected state to generate an output signal corresponding to a high input signal, a first voltage level is generated at a node and output as the control signal for the output driver, providing for an initial pull-up transition for the output signal. A second voltage level is subsequently generated at the node and output as the control signal for the output driver, providing for a steady-state voltage level for the high output signal.

Abstract: A phase detector is described. The phase detector receives a data signal from an external circuit. The phase detector generates a first signal when a transition edge of the clock signal occurs after a transition edge of the data signal. The phase detector generates a second signal when the transition edge of the clock signal occurs before the transition edge of the data signal and generates a third signal when the data signal remains in a same signal state for at least two transition edges of a same type of the clock signal.

Abstract: A method of forming an antifuse. A first conductive layer is deposited over a substrate. Next, a capping layer is deposited onto the conductive layer. An antifuse layer is then deposited onto the capping layer. A barrier layer is then deposited onto the antifuse layer. Next, the first conductive layer, the capping layer, the antifuse layer, and the barrier layer are patterned into a metal stack. A disposable post is then formed on the barrier layer of the patterned metal stack. The barrier layer and the antifuse layer are then etched substantially in alignment with the disposable post to leave a first metal interconnect. Next, an insulating layer is formed over the substrate including the first metal interconnect and the disposable post wherein the insulating layer is made substantially planar with the disposable post. The disposable post is then removed to form an aperture in the insulating layer. A second conductive layer is then deposited into the aperture and onto the barrier layer.

Abstract: A pseudo-differential sense amplifier for sensing the state of an array memory cell by reference to a reference cell in a predetermined state. The sense amplifier has an input stage coupled to the array memory cell, which provides signals to a differential stage from which an output is generated. The input stage has reference and array side cascode circuits in which the components are matched on each side so as to eliminate process, temperature, and other extraneous variations from influencing the differential output. An enabling signal to the array side of the input stage is delayed with respect to the reference side such that voltage fluctuations externally introduced into the signals passed from the input stage to the differential stage do not cause erroneous switching and/or glitches to appear at the sense amplifier output.

Abstract: A programmable logic device (PLD) architecture that minimizes the skew in the outputs of PLD devices in response to input signal transitions. The architecture emulates the worst case response condition of the memory array portion of the PLD and builds it into a dedicated emulation signal path, which is in parallel with the signal path of the real data between the input and output of the PLD. The output of the emulation signal path then controls the real data output path and thus the output of the PLD. The PLD output equals the real data path output only when the output of the emulation signal path is valid.

Abstract: An overvoltage tolerant output buffer circuit for coupling an integrated circuit (IC) to external electrical apparatus by way of a contact pad or other input/output connection. An overvoltage protection circuit is provided to bias the semiconductor or well region containing the pull-up driving transistors of the output buffer so as to reduce current injected to the supply rail of the IC from the contact pad during an overvoltage condition. The protection circuit is arranged to bias the substrate on the basis of a potential difference between the supply rail and the contact pad so that neither of the supply rail and contact pad substantially exceeds the potential of the substrate. Circuitry is also provided to block signals from being passed to the buffer circuit from other circuits on the IC, and for preventing a gate-source potential difference from being applied to the pull-up driving transistors during the overvoltage condition.

Abstract: A variable slew control for output circuits is disclosed. The slew control circuit automatically adjusts the rate in which voltage on a slew node is driven to a reference voltage, minimizing noise at the output device driver. The variable slew control decreases the slew rate of the slew node during periods when di/dt is at a high level, but allows the voltage on the slew node to drop at faster rates during times when di/dt at the output driver is low.

Abstract: A programmable circuit includes: (a) a plurality of programmable cells; (b) a sense amplifier for detecting states of the plurality of programmable cells; (c) a programmable unit for receiving a signal from the sense amplifier; (d) a configuration circuit for configuring the programmable unit; and (e) a sense control circuit coupled to the sense amplifier and to the configuration circuit for enabling or disabling the sense amplifier using a configuration signal of the configuration circuit. The programmable circuit may further include: (f) a second programmable unit for receiving the signal from the sense amplifier; and (g) a second configuration circuit for configuring the second programmable unit, where the sense control circuit is coupled to the second configuration circuit for enabling or disabling the sense amplifier using a second configuration signal of the second configuration circuit.

Abstract: A method of etching an oxide layer is disclosed. First, a resist layer is formed on an oxide layer on a substrate. Next, a photosensitive layer is formed on the oxide layer and patterned to expose regions of the oxide layer to be removed. The exposed regions may overlie a nitride layer, and may overlie a structure such as a polysilicon gate. The etch is performed such that polymer deposits on the photosensitive layer, thus eliminating interactions between the photosensitive layer and the plasma. In this way, a simple etch process allows for good control of the etch, resulting in reduced aspect ratio dependent etch effects, high oxide:nitride selectivity, and good wall angle profile control.

Abstract: An output buffer with a variable output impedance is described. The buffer is designed so that the output impedance is set relatively low during the initial portion of the output transition in which the step would occur. The output impedance is increased near the end of the transmission to approximate the characteristic impedance of a transmission line driven by the buffer. Specifically, a first feedback circuit in the variable impedance output buffer outputs a first control signal in a first state during a first portion of the output transition. The first feedback circuit outputs the first control signal in a second state during a second portion of the output transition after the first portion. A first switched resistive element receives the first control signal from the first feedback circuit. The first switched resistive element increases the output impedance of the buffer in response to the first control single being in the second state.

Abstract: An output preconditioning circuit with an output level latch is provided to precondition the output to an intermediate level and to clamp the output to that level before the actual data from a memory cell arrives at the output. Since the actual data has to charge or discharge the output from some intermediate level rather than the maximum output swing level or the minimum output swing level, as in the normal case, this results in a reduced delay in charging or discharging the output. The output preconditioning circuit which may be coupled to a heavy load or a light load can eliminate oscillation of the output because of the output level latch.

Abstract: A pull-down output device controls the discharge of an output signal for a pull-down transition. A pull-down control signal is generated in response to an input signal. A control signal is generated in response to the pull-down control signal to couple a first voltage terminal to a control signal node. The output signal is initially discharged as a bipolar transistor is turned-on by the control signal at the node and couples the output signal to a second voltage terminal. The first voltage terminal is decoupled from the control signal node as a control signal is generated to couple the output signal to the control signal node. The output signal is further discharged through the bipolar transistor. The discharge of the output signal is thus controlled.

Abstract: A method is described for eliminating overerasure in a nonvolatile memory that includes a plurality of memory cells, each having a control gate, a floating gate, a drain, and a source. The nonvolatile memory is electrically erased until each of the plurality of memory cells has a threshold voltage below a predetermined erased voltage state. The nonvolatile memory then undergoes an equalization programming operation by applying an equalization programming voltage to the control gate of each of the plurality of memory cells such that the threshold voltage of each of the plurality of memory cells is saturated to the predetermined erased voltage state. The equalization programming voltage determines the predetermined erased voltage state. An apparatus for eliminating overerasure in the nonvolatile memory during erasing is also described.

Abstract: A sense amplifier circuit having a pair of complementary inputs and a pair of complementary outputs with voltage swing limiter and cross-coupled feedback to tail devices. The sense amplifier circuit comprises first differential amplifier for receiving the pair of complementary inputs to generate first output of the pair of complementary outputs. The first differential amplifier is coupled to a first current source device for biasing. The circuit also comprises second differential amplifier for receiving the pair of complementary inputs to generate second output of the pair of complementary outputs. The second differential amplifier is coupled to a second current source device for biasing. A voltage swing limiter is coupled to the pair of complementary outputs of the first and second differential amplifiers for limiting the voltage swing of the pair of complementary outputs. A feedback circuit is coupled to feed the outputs back to drive the other tail device.

Abstract: The use of separate masks to pattern the same layer of material formed over a semiconductor substrate serves to reduce or avoid lithographic rounding effects. A layer of material formed over a semiconductor substrate may be patterned in accordance with separate masks. A first mask may have a feature which is substantially perpendicular to a feature of a separate second mask. Where the layer is patterned to form transistor gates, the minimum amount each transistor gate should extend over the edge of its active region under the endcap rule may be reduced. In this regard, a line pattern mask and a gap mask are used to avoid lithographic rounding effects in forming the transistor gates. Semiconductor devices may thus be fabricated with higher packing densities as transistors may be placed closer to one another.

Abstract: The present invention provides a method for the formation of interconnects and landing pads having a thin, conductive film underlying the plug of an associated contact or via hole. In accordance with the preferred embodiment of the present invention, a silicon substrate is provided having at least one device region formed at the surface of the substrate. An insulating layer is deposited over the substrate having at least one contact hole formed through the insulating layer to expose the device region. A first blanket layer of titanium is deposited as a tungsten adhesion layer over the insulating layer and the exposed device region within the contact hole. A second blanket layer of titanium-tungsten or titanium-nitride is then deposited as a tungsten barrier layer over the adhesion layer. Subsequently, a blanket contact plug layer comprising tungsten is deposited over the barrier layer by chemical vapor deposition.

Abstract: A differential latch sense amplifier for memories has (a) a first differential input circuit for detecting and shifting the voltage levels of the first and second input signals and coupled to first and second sense nodes, (b) a cross-coupled latch for providing gain to the first and second sense nodes, (c) a precharge circuit for precharging and equalizing the first and second sense nodes, (d) a first tristatable output driver for providing a first feedback, for outputting the voltage of the first sense node to a first output node, and for receiving data, (e) a second tristatable output driver for providing a second feedback, for outputting the voltage of the second sense node to a second output node, and for receiving data, and (f) a first feedback circuit for increasing the voltage gain and decreasing the sense output response time at the first and second sense nodes and for being controlled by the first and second tristatable output drivers.

Abstract: A method for forming an alignment mark during semiconductor device manufacturing. A first alignment mark having a first step height is formed in a semiconductor substrate. An interlayer dielectric is formed over the alignment mark and planarized to a first thickness. During contact/via etch an opening is formed through the first dielectric layer away from the first alignment mark. The opening is then filled with a material until the material in the bottom of the opening has a thickness less than thickness of the planarized dielectric layer.

Abstract: A user configurable circuit contains clock logic, a switching element and a data path circuit. Input data is received in the switching element, and the switching element and the data path circuit constitute the entire data path for the circuit. A plurality of user configurable inputs are received to configure the circuit for a particular user application. The clock logic and the switching element implement a logic function that is configurable by the user configurable inputs. The logic function is pre-processed in the clock logic so that minimal delay occurs in the data path. In addition, the propagation delay through the switching element and the register is independent of the user configurable inputs. The user configurable circuit of the present invention has application for use as a macro cell for a programmable logic device permitting the user to configure the circuit as a D-type flip-flop, a T-type flip-flop. In addition, the user selects the polarity for the output circuit.

Abstract: A translator for translating signals from a CML or ECL circuit to signals that are compatible with CMOS or TTL voltage levels is disclosed. The translator has minimum power consumption and provides switching and drive characteristics that are independent of the threshold voltage, power supply voltage, temperature and process variations. The translator includes the following components: a bias reference generator for receiving a first bias voltage and generating a second bias voltage; an input circuit for receiving the input signals; a cascode circuit for receiving the second bias voltage, having a controlled current and outputting the output signals; and a current-mirror circuit. The first bias voltage is at the mid-point of the logic swing of the input signals, and the bias reference generator provides the second bias voltage to generate the controlled current in the switching stage of the translator.