Abstract: An integrated circuit and method are provided for sensing activity such as acceleration in a predetermined direction. The integrated released beam sensor preferably includes a switch detecting circuit region and a sensor switching region connected to and positioned adjacent the switch detecting circuit region. The sensor switching region preferably includes a fixed contact layer, remaining portions of a sacrificial layer on the fixed contact layer, and a floating contact on the remaining portions of the sacrificial layer and having only portions thereof directly overlying the fixed contact layer and in spaced relation therefrom in a normally open position and extending lengthwise generally transverse to the predetermined direction so that the floating contact contacts the fixed contact layer responsive to acceleration in the predetermined direction. The floating contact is preferably a released beam which is released by opening a window or removing unwanted portions of the sacrificial layer.

Abstract: A mask is used for lightly doped drain and halo implants in an integrated circuit device. The mask exposes only portions of the substrate adjacent to field effect transistor gate electrodes. Since the halo implant is made only near the transistor channels, where it performs a useful function, adequate device reliability and performance is obtained. Since the halo implant is masked from those portions of the active regions for which it is not necessary, active region junction capacitances are lowered. Such lowered capacitances result in an improved transistor switching speed. The mask used to define the lightly doped drain and halo implant region can be easily formed from a straight forward combination of already existing gate and active area geometries.

Abstract: A method of forming an isolation region in an integrated circuit and an integrated circuit formed thereby. A method preferably includes forming at least one trench in a semiconductor substrate, forming an insulation layer of material in the at least one trench and on peripheral regions of the at least one trench of the semiconductor substrate, forming a sacrificial layer of material on the insulation layer having a different polishing rate than the insulation layer, and polishing the layer having the different polishing rate and portions of the insulation layer so that the sacrificial layer having the different polishing rate and portions of the insulation layer are removed, so that other portions of the insulation layer remain in the at least one trench of the substrate, and so that the upper surface of the at least one trench and the peripheral regions thereof in combination provide a substantially planar surface.

Abstract: A precision oscillator includes a capacitor, a charging current source, a discharging current source, a switch for alternatingly connecting the capacitor to the charging current source and the discharging current source, and a hysteretic comparator connected to the capacitor for producing an oscillating signal responsive to charging and discharging the capacitor. The oscillator may also preferably include a duty cycle controller connected to at least one of the charging current source and the discharging current source for setting the charging current and/or the discharging current to thereby set a duty cycle of the oscillating signal by setting a ratio of the charging and discharging currents. The charging current source may have a current setting input for permitting setting of a charging current to the capacitor, and the discharging current source may have a current setting input for permitting setting of a discharging current from the capacitor.

Abstract: A tri-state I/O buffer and a method of inhibiting current to an I/O buffer arranged to be powered by a supply voltage and to drive an output terminal are provided. The I/O buffer preferably has an output driving circuit connected to the supply voltage for driving the output terminal and includes a first plurality of transistors defining an isolated floating well circuit for operatively connecting the output terminal to the supply voltage and a second plurality of transistors defining a pull-down circuit for operatively connecting the output terminal to ground. An input control circuit is connected to the output driving circuit and the supply voltage, and is arranged to receive a buffer input signal for controlling the buffer input signal to the output driving circuit.

Abstract: An integrated circuit preferably includes a plurality of enhancement-mode MOSFETs on a substrate with each MOSFET having an initial threshold voltage, and a plurality of resistors connected to define a resistor voltage divider for passively biasing the MOSFETs to produce an absolute value of an effective threshold voltage of each MOSFET to be lower than an absolute value of the initial threshold voltage. Accordingly, the effective threshold voltages may set to below a predetermined value, and lower supply voltages thereby readily accommodated. For integrated circuits having all n-channel MOSFETs, the threshold voltages are positive, and the voltage divider can be set accordingly. The invention is advantageously also used in CMOS integrated circuits having both p-channel and n-channel MOSFETs. The resistor voltage divider may preferably be set or trimmed after forming the MOSFETs.

Abstract: An integrated circuit includes a plurality of MOSFETs on a substrate. The plurality of MOSFETs preferably includes at least one MOSFET having a first conductivity type and at least one MOSFET having a second conductivity type. Each MOSFET has an initial threshold voltage. The integrated circuit also preferably includes first and second biasing circuits which selectively bias only a selected well a corresponding conductivity type of the plurality of MOSFETs to produce an absolute value of an effective threshold voltage of only the selected MOSFET which is lower than an absolute value of the initial threshold voltage thereof and thereby inhibit a high standby current for the integrated circuit. Method aspects of the invention are also disclosed.

Abstract: An integrated circuit and method are provided for sensing activity such as temperature variations in a surrounding environment. The integrated released beam sensor preferably includes a switch detecting circuit region and a sensor switching region connected to the switch detecting circuit region. The sensor switching region preferably includes a fixed contact layer, a sacrificial layer on the fixed contact layer, and a floating contact on the sacrificial layer and having portions thereof overlying the fixed contact layer in spaced relation therefrom in an open switch position and extending lengthwise generally transverse to a predetermined direction. The floating contact preferably includes at least two layers of material. Each of the at least two layers have a different thermal expansion coefficient so that the floating contact displaces in the predetermined direction responsive to a predetermined temperature variation so as to contact the fixed contact layer and thereby form a closed switch position.

Abstract: A DC-to-DC converter includes an error amplifier; a ramp generator for generating a ramp signal at the first input of the error amplifier independent of the output of the error amplifier and so that the output of the error amplifier ramps up at a relatively slow rate to avoid overshoot of the desired output voltage of the converter during the start-up phase of the converter; and a ramp disable circuit for disabling the ramp signal upon reaching a value corresponding to the normal operating phase of the converter. The DC-to-DC converter preferably includes at least one power switch and pulse width modulation (PWM) control circuit cooperating with the power switch to provide a desired output voltage of the converter. The ramp generator in one embodiment comprises a current source and an external capacitor connected thereto. In yet another embodiment, the ramp generator may be provided by a staircase ramp generator comprising an amplifier and an integrating capacitor connected thereto.

Abstract: A mask is used for lightly doped drain and halo implants in an integrated circuit device. The mask exposes only portions of the substrate adjacent to field effect transistor gate electrodes. Since the halo implant is made only near the transistor channels, where it performs a useful function, adequate device reliability and performance is obtained. Since the halo implant is masked from those portions of the active regions for which it is not necessary, active region junction capacitances are lowered. Such lowered capacitances result in an improved transistor switching speed. The mask used to define the lightly doped drain and halo implant region can be easily formed from a straight forward combination of already existing gate and active area geometries.

Abstract: An integrated circuit having enhanced testing capabilities and a method of testing an integrated circuit are provided. The integrated circuit preferably includes a substrate and a memory block on the substrate. The memory block preferably has a plurality of memory cells arranged in a plurality of rows and a plurality of columns within a defined area on the substrate, at least one bit line connected to each of the plurality of memory cells and defining a column, at least one word line connected to each of the plurality of memory cells and defining a row, and sense amplifying means connected to the at least one bit line for sensing a state of an addressed memory cell in at least one of the plurality of columns. The integrated circuit also includes a selectable stress tester on the substrate and connected to the memory block for selectively stress testing only portions of the memory block and not other portions so as to determine whether to accept or reject a memory block.

Abstract: An integrated circuit and method are provided for generating current for low power applications. The integrated circuit preferably includes a current generating circuit responsive to a supply voltage for generating a first reference current and a temperature compensating voltage controlling circuit for generating a temperature compensated voltage control signal during temperature variations. A bias controlling circuit is preferably connected to the current generating circuit and the temperature compensating voltage control circuit for biasingly controlling the temperature compensating voltage control circuit. A current output controlling circuit is connected to the current generating circuit and the temperature compensating voltage controlling circuit for controlling a second temperature compensated reference current responsive to the temperature compensated voltage control signal so as to generate a high output source current even during low temperature conditions.

Abstract: An integrated circuit includes a plurality of MOSFETs having channels of a first conductivity type, and having active control of an effective threshold voltage of the MOSFETs to be less than an absolute value of an initial threshold voltage. In this embodiment, a first MOSFET has a channel of the first conductivity type, and a second MOSFET is connected to the first MOSFET and has a channel of a second conductivity type. The second MOSFET is preferably biased to a pinch-off region and cooperates with the first MOSFET for generating a control signal related to an effective threshold voltage of the first MOSFET. Moreover, the circuit preferably generates a bias voltage to the plurality of MOSFETs and to the first MOSFET based upon the control signal to set an effective threshold voltage of the plurality of MOSFETs to have an absolute value less than an absolute value of the initial threshold voltage and, more preferably, to a reference voltage. Accordingly, lower supply voltages can be readily accommodated.

Abstract: A method is provided for a planar surface of a semiconductor integrated circuit, and an integrated circuit formed according to the same. A conductive layer is formed over a substrate. A silicon nitride layer is formed over the conductive layer. A photoresist layer is then formed and patterned over the silicon nitride layer. The silicon nitride layer and the conductive layer are etched to form an opening exposing a portion of the substrate. The photoresist layer is then removed. The exposed substrate and a portion of the conductive layer exposed along the sidewalls in the opening are oxidized. An planarizing insulating layer such as spin-on-glass is formed over the silicon nitride layer and in the opening. The insulating layer is etched back to expose the silicon nitride wherein an upper surface of the insulating layer is level with an upper surface of the conductive layer. The silicon nitride layer is then removed. A planar silicide layer is then formed over the conductive layer.

Abstract: A method is provided for a planar surface of a semiconductor integrated circuit, and an integrated circuit formed according to the same. A gate electrode is formed over a substrate having source/drain regions adjacent to the gate electrode and in the substrate. A silicon dioxide layer is formed over the gate electrode and a portion of the substrate not covered by the gate electrode. A first phosphorous doped spin-on-glass layer is formed over the silicon dioxide layer, wherein the spin-on-glass is doped to a concentration sufficient to facilitate gettering of charge mobile ions. An opening is then formed in the spin-on-glass layer and the silicon dioxide layer exposing a portion of the source drain region.

Abstract: A motor control circuit, including a filter amplifier which includes a clamping circuit to limit the maximum voltage of the filter amplifier. The filter amplifier is clamped to essentially the same level as the following error amplifier, which drives the power transistor which drives the motor. Thus, the requisite control voltage is normally present anyway (since this voltage is used to limit the amount of maximum current in the motor). Since the corresponding level of current is selected to ensure adequate current during start up, this signal is therefore appropriate to limit the output voltage of the filter amplifier. This improvement adds very little circuit complexity, and reduces the settling time of the motor controller at startup.

Abstract: A mask is used for lightly doped drain and halo implants in an integrated circuit device. The mask exposes only portions of the substrate adjacent to field effect transistor gate electrodes. Since the halo implant is made only near the transistor channels, where it performs a useful function, adequate device reliability and performance is obtained. Since the halo implant is masked from those portions of the active regions for which it is not necessary, active region junction capacitances are lowered. Such lowered capacitances result in an improved transistor switching speed. The mask used to define the lightly doped drain and halo implant region can be easily formed from a straight forward combination of already existing gate and active area geometries.

Abstract: An integrated circuit includes a plurality of MOSFETs on a substrate. A plurality of sensing MOSFETs are used to generate a plurality of comparison signals based upon comparing signals related to the sensed initial threshold voltages to respective reference voltages from a spread of high to low reference voltage values. The MOSFETs are biased to have a desired effective threshold voltage based upon the plurality of comparison signals. Logic decoding circuits accept the plurality of comparison signals and generate at least one bias control signal. Bias circuits are responsive to the at least one bias control signal for generating a desired bias voltage from among a plurality of bias voltages having a spread of high to low bias voltage values to thereby bias the plurality of MOSFETs to the desired effective threshold voltage. Method aspects of the invention are also disclosed.

Abstract: A current source for generating a current that is relatively stable over variations in the power supply voltage and temperature, and over variations in process parameters is disclosed. The current source includes a bias circuit, for producing a compensating bias voltage, and a current mirror. The bias circuit utilizes a voltage divider to generate a divided voltage based on the power supply value. The divided voltage is applied to the gate of a modulating transistor (biased in saturation) in a first current mirror, which controls a current applied to a linear load device. The voltage across the load device determines the bias voltage, which is in turn applied to the gate of a transistor in the reference leg of a second current mirror. The bias voltage controls the current in the reference leg of the second current mirror, and an output leg mirrors the second reference current to produce a stable output current.

Abstract: A CMOS SRAM cell has a polycrystalline silicon signal line between a common node, which is the data storage node, and the power supply. A field effect device is fabricated within this polycrystalline silicon signal line. The channel of the field effect device is separated from an active region in the substrate by a thin gate dielectric, and the active region within the substrate functions as the control gate for the field effect device. Such a device can be used to provide polycrystalline silicon P-channel transistors for use in CMOS SRAM cells.