Patents Assigned to STMicroelectronics, Inc.
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Patent number: 6297698Abstract: A circuit for regulating the gain of a variable differential gain amplifier. In one embodiment, a fully differential amplifier amplifies the outputs of the variable gain amplifier. The outputs of the fully differential amplifier are applied to a three input comparator so that if either of the outputs are greater than a reference voltage, a control signal is generated which is used to regulate the gain of the variable gain amplifier. In other embodiments, an analog OR function is used as an input to a conventional two input comparator in place of the three input comparator. In another embodiment, outputs of the variable gain amplifier are passed through switches to a scaling circuit which either voltage divides or amplifies and combines the outputs before application to a comparator. In each case, known asymmetries can be compensated for by independent gain control of each of the outputs of the variable gain differential amplifier.Type: GrantFiled: April 28, 2000Date of Patent: October 2, 2001Assignee: STMicroelectronics, Inc.Inventor: Michael J. Callahan, Jr.
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Patent number: 6297919Abstract: A write head is described having a switchable damping resistance coupled in parallel with an inductor. The damping resistance is decoupled from the inductor by rendering a transistor nonconductive when a direction of current in the inductor changes. The damping resistance is then coupled to the inductor before oscillations begin in the current in the inductor. The decoupling of the damping resistor eliminates power dissipation in the damping resistor during a change in the direction of current in the inductor.Type: GrantFiled: October 24, 1997Date of Patent: October 2, 2001Assignee: STMicroelectronics, Inc.Inventors: Albino Pidutti, Axel Alegre de La Soujeole
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Patent number: 6297996Abstract: A memory device with a test mode control circuit for entering a test mode responsive to a high on the Vss pin or a low on the Vcc pin that supply power to the output pins during normal operation of the memory device. In test mode the wordlines and bitlines of the memory remain active from the time they are activated, typically when the clock switched from a first to a second logic state, until the clock switches back to the first logic state.Type: GrantFiled: December 9, 1999Date of Patent: October 2, 2001Assignee: STMicroelectronics, Inc.Inventor: David C. McClure
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Patent number: 6295224Abstract: A circuit and method is disclosed for a memory cell for a static random access memory. The memory cell includes a pair of cross-coupled CMOS logic inverters that are connected together to form a latch, and a pair of p-channel transmission gate transistors that are connected to the logic inverters for selectively providing access to the latch. The layout of the memory cell includes a rectangular active area in which the p-channel transistors of the memory cell are located. The rectangular active area abuts a similar active area of an adjacent memory cell along a row of memory cells so as to form a single rectangular active area for the p-channel memory cell transistors. The rectangular active area reduces the occurrence of fabrication-related phenomena that adversely effect the performance of the memory cell.Type: GrantFiled: December 30, 1999Date of Patent: September 25, 2001Assignee: STMicroelectronics, Inc.Inventors: Tsiu Chiu Chan, Mehdi Zamanian, David Charles McClure
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Patent number: 6294939Abstract: A substantially noise-free data input buffer for an asynchronous device, such as a static random access memory (SRAM). The input buffer generates either a logical true or complement output signal representation of a data input signal and includes timing circuitry to delay an edge transition on the output signal for a predetermined period of time in response to a signal edge transition appearing on the data input signal. The input buffer further includes edge transition detection (ETD) circuitry for generating an initialization signal in response to the generation of the data output signal.Type: GrantFiled: October 30, 1998Date of Patent: September 25, 2001Assignee: STMicroelectronics, Inc.Inventor: David C. McClure
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Patent number: 6291344Abstract: Methods of forming, in an integrated circuit, aluminum-silicon contacts with a barrier layer is disclosed. The barrier layer is enhanced by the provision of titanium oxynitride layers adjacent the silicide film formed at the exposed silicon at the bottom of the contact. The titanium oxynitride may be formed by depositing a low density titanium nitride film over a titanium metal layer that is in contact with the silicon in the contact; subsequent exposure to air allows a relatively large amount of oxygen and nitrogen to enter the titanium nitride. A rapid thermal anneal (RTA) both causes silicidation at the contact location and also results in the oxygen and nitrogen being gettered to what was previously the titanium/titanium nitride interface, where the oxygen and nitrogen react with the titanium metal and nitrogen in the, atmosphere to form titanium oxynitride. The low density titanium nitride also densifies during the RTA.Type: GrantFiled: September 13, 2000Date of Patent: September 18, 2001Assignee: STMicroelectronics, Inc.Inventors: De-Dul Liao, Yih-Shung Lin
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Patent number: 6292383Abstract: A dynamic random access memory (DRAM) device is disclosed. The DRAM device includes a memory cell array having a twisted bit line architecture. The memory cell array includes at least one pair of redundant rows of memory cells. Redundant row decode circuitry is capable of configuring the pair of redundant rows to replace any one row of memory cells having a defect. Each pair of bit lines is coupled to a distinct memory cell from each redundant row of the redundant row pair so that both the true and complement version of a data value is maintained by the redundant row pair. Rows of reference cells are disconnected and/or disabled during a memory access operation involving the redundant row pair. The use of a pair of redundant rows of memory cells to replace a single row of memory cells having a defect substantially reduces the complexity of decode circuitry for enabling the rows of reference cells.Type: GrantFiled: April 25, 2000Date of Patent: September 18, 2001Assignee: STMicroelectronics, Inc.Inventor: James L. Worley
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Patent number: 6291845Abstract: A field-effect transistor structure wherein a single patterned thin film semiconductor layer: is monocrystalline, and epitaxially matched to and dielectrically isolated from an underlying body region, in channel locations; and is polycrystalline in source/drain locations which abut said channel locations.Type: GrantFiled: August 24, 1999Date of Patent: September 18, 2001Assignee: STMicroelectronics, Inc.Inventor: Richard A. Blanchard
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Patent number: 6291337Abstract: Two improved process steps of eliminating cracks within TiN and/or BPSG layers after the RTP process are provided. The first is to provide a low deposition power, preferably below 6.5 KWH, and a high process pressure, preferably above 5.6 mTorr, to the TiN layer. No crack is found for this improved TiN deposition process when the RTP temperature rises from 450° C. to about 700° C. The second is to provide a low RTP temperature, preferably below 595° C., to the semiconductor wafer. No crack, again, is found by using this low RTP temperature.Type: GrantFiled: February 20, 1998Date of Patent: September 18, 2001Assignee: STMicroelectronics, Inc.Inventor: Ardehsir J. Sidhwa
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Patent number: 6287963Abstract: A method is provided for depositing aluminum thin film layers to form contacts in a semiconductor integrated circuit device. All or some of the deposition process occurs at relatively low deposition rates at a temperature which allows surface migration of the deposited aluminum atoms. Aluminum deposited under these conditions tends to fill contact vias without the formation of voids. The deposition step is periodically interrupted.Type: GrantFiled: April 6, 1995Date of Patent: September 11, 2001Assignee: STMicroelectronics, Inc.Inventors: Fusen E. Chen, Fu-Tai Liou, Girish A. Dixit, Che-Chia Wei
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Patent number: 6288521Abstract: An electronic device battery pack for a battery requiring cycling to prolong lifetime is divided into at least two parallel cells for which the charging state is automatically maintained. When external power is available and one or more cells is substantially discharged, the substantially discharged cell(s) are selected one at a time to be fully drained and recharged. A partially discharged but not substantially discharged cell will be left in that state until use of the electronic device has substantially discharged the cell. Once a cell has been recharged, the next substantially discharged cell is drained and recharged, and so on until all cells are fully charged. If the charging of a cell is interrupted by removal of the external power, another cell is utilized to provide power to the electronic device and recharging is resumed once the external power is restored.Type: GrantFiled: September 8, 2000Date of Patent: September 11, 2001Assignee: STMicroelectronics, Inc.Inventor: James Chester Meador
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Patent number: 6284584Abstract: An integrated circuit memory fabrication process and structure, in which salicidation is performed on the periphery (and optionally on the ground lines) of a memory chip, but not on the transistors of the memory cells.Type: GrantFiled: June 10, 1997Date of Patent: September 4, 2001Assignee: STMicroelectronics, Inc.Inventors: Robert Louis Hodges, Loi Ngoc Nguyen
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Patent number: 6285801Abstract: A filter reduces artifacts, such as grid noise and staircase noise, in block-coded digital images with image block boundaries. The type of filtering is determined after an estimation of the image global metrics and local metrics. For areas of the image near grid noise, the filter performs low pass filtering. For image fine details, such as edges and texture, no filtering is performed so that masking is avoided. The filter operates in intra-field mode and uses a fuzzy logic process, pixel deltas, and dual ramp generators to determine the horizontal and vertical length of a processing window surrounding an image block boundary.Type: GrantFiled: May 29, 1998Date of Patent: September 4, 2001Assignee: STMicroelectronics, Inc.Inventors: Massimo Mancuso, Antonio Maria Borneo
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Patent number: 6281734Abstract: A reference voltage trim circuit includes a voltage follower receiving the reference voltage to be trimmed, with one or more resistive loads providing predefined voltage shifts serially connected between the output of the voltage follower and the output of the trim circuit. The voltage follower includes a current mirror differential amplifier receiving the reference voltage at one input and the output of the voltage follower at the other input, and a transistor with a resistive load connected between the power supply voltages and receiving the output of the current mirror differential amplifier at the transistor's gate. The resistive loads provide varying preselected voltage drop and are each shunted by corresponding fuses, with the entire series of resistive loads shunted by a master fuse. To trim the reference voltage, at least the master fuse is blown, together with the fuse(s) shunting resistive loads which combine to result in the desired trim voltage.Type: GrantFiled: December 31, 1999Date of Patent: August 28, 2001Assignee: STMicroelectronics, Inc.Inventors: David C. McClure, Rong Yin
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Patent number: 6278337Abstract: An integrated oscillator and associated methods are provided for providing clock signals. The integrated oscillator preferably includes a micro-mechanical oscillating circuit for providing an oscillating clock signal. The micro-mechanical oscillating circuit preferably includes a support layer, a fixed layer positioned on a support layer, remaining portions of a sacrificial layer positioned only on portions of the fixed layer, and an oscillating layer positioned on the remaining portions of the sacrificial layer, overlying the fixed layer in spaced relation therefrom, and extending lengthwise generally transverse to a predetermined direction for defining a released beam for oscillating at a predetermined frequency. The spaced relation is preferably formed by removal of unwanted portions of the sacrificial layer.Type: GrantFiled: October 5, 1999Date of Patent: August 21, 2001Assignee: STMicroelectronics, Inc.Inventors: Tsiu Chiu Chan, Melvin Joseph DeSilva, Syama Sundar Sunkara
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Patent number: 6275078Abstract: A pair of equivalent controlled impedance buffers are connected in a push-pull configuration to a transformer primary coil. A pair of equivalent pre-drivers are connected to the pair of buffers. Each pre-driver receives a driver input signal and outputs a buffer input signal and a proportional flyback compensation signal. Each buffer receives the buffer input signal generated from one of the pre-drivers for buffered output as a line driver signal to the primary coil which induces a flyback voltage effect in each buffer. Each buffer further receives the flyback compensation signal generated from the other one of the pre-drivers, with the buffer operating to cancel the flyback voltage effect induced in that buffer using the flyback compensation signal received from the other one of the pre-drivers. An adjustment circuit further outputs an adjustment signal for application to an adjustable current source.Type: GrantFiled: February 4, 2000Date of Patent: August 14, 2001Assignee: STMicroelectronics, Inc.Inventor: Oleksiy Zabroda
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Patent number: 6271063Abstract: A six transistor static random access memory (SRAM) cell with thin-film pull-up transistors and method of making the same includes providing two bulk silicon pull-down transistors of a first conductivity type, two active gated pull-up thin-film transistors (TFTs) of a second conductivity type, two pass gates, a common word line, and two bit line contacts. The bulk silicon pull-down transistors, two active gated pull-up TFTs, and two pass gates are connected at four shared contacts. In addition, the two bulk silicon pull-down transistors and the two active gated pull-up TFTs are formed with two polysilicon layers, a first of the polysilicon layers (poly1) is salicided and includes poly1 gate electrodes for the two bulk silicon pull-down transistors. A second of the polysilicon layers (poly2) includes desired poly2 stringers disposed along side edges of the poly1 gate electrodes, the desired poly2 stringers forming respective channel regions of the pull-up TFTs.Type: GrantFiled: June 14, 2000Date of Patent: August 7, 2001Assignee: STMicroelectronics, Inc.Inventors: Tsiu Chiu Chan, Frank Randolph Bryant
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Patent number: 6271137Abstract: A method is provided for forming improved quality interlevel aluminum contacts in semiconductor integrated circuits. A contact opening is formed through an insulating layer. A barrier layer is deposited over the surface of the integrated circuit. An aluminum layer is then deposited at relatively low deposition rates at a temperature which allows improved surface migration of the deposited aluminum atoms. Aluminum deposited under these conditions tends to fill contact vias without the formation of voids. The low temperature deposition step can be initiated by depositing aluminum while a wafer containing the integrated circuit device is being heated from cooler temperatures within the deposition chamber.Type: GrantFiled: November 1, 1993Date of Patent: August 7, 2001Assignee: STMicroelectronics, Inc.Inventors: Fu-Tai Liou, Fusen E. Chen
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Patent number: 6265312Abstract: A tungsten film stack is formed on a wafer using a deposition chamber by first depositing a nucleation on the wafer in the presence of a carrier gas, such as nitrogen. Following deposition of the nucleation, excess carrier gas is evacuated from the deposition chamber. Then, following evacuation of the excess carrier gas, a tungsten fill is deposited over the nucleation.Type: GrantFiled: August 2, 1999Date of Patent: July 24, 2001Assignee: STMicroelectronics, Inc.Inventors: Ardeshir Jehangir Sidhwa, Stephen John Melosky
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Patent number: 6262617Abstract: A semiconductor device is provided which has a plurality of output drivers whose slew rates are differentially controlled. The slew rates of the output drivers are controlled by a control means such that the slew rate of at least one of the output drivers is different than the slew rate of another output driver. Preferably, the slew rates are differentially controlled such that an output driver that drives a signal that reaches an output pin of a semiconductor package later slews at a faster rate than an output driver that drives a signal that reaches an output pin of a semiconductor package earlier. In this way all of the output pins of a semiconductor package can be driven to change states at approximately the same time. The slew rates of the output drivers can be differentially controlled through the utilization of programmable resistors.Type: GrantFiled: December 30, 1994Date of Patent: July 17, 2001Assignee: STMicroelectronics, Inc.Inventor: David Charles McClure