Patents by Inventor Ashok Kapoor
Ashok Kapoor has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 11444696Abstract: Various embodiments of a micro-disc modulator as well as a silicon photonic device and an optoelectronic communication apparatus using the micro-disc modulator are described. In one aspect, a device includes a SOI substrate and a silicon photonic structure formed on a primary surface of the SOI substrate. The semiconductor substrate includes a silicon waveguide and a micro-disc modulator. The micro-disc modulator is adjacent to the silicon waveguide and has a top surface substantially parallel to the primary surface of the SOI substrate. The top surface of the micro-disc modulator includes one or more discontinuities therein. The micro-disc modulator may be a multi junction micro-disc modulator having two vertical p-n junctions with a single resonance frequency to achieve high-speed modulation and low-power consumption.Type: GrantFiled: July 8, 2014Date of Patent: September 13, 2022Assignee: PhotonIC International Pte. Ltd.Inventors: Birendra Dutt, Ashok Kapoor, Weiwei Song, Raj Rajasekharan
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Publication number: 20160013865Abstract: Various embodiments of a micro-disc modulator as well as a silicon photonic device and an optoelectronic communication apparatus using the micro-disc modulator are described. In one aspect, a device includes a SOI substrate and a silicon photonic structure formed on a primary surface of the SOI substrate. The semiconductor substrate includes a silicon waveguide and a micro-disc modulator. The micro-disc modulator is adjacent to the silicon waveguide and has a top surface substantially parallel to the primary surface of the SOI substrate. The top surface of the micro-disc modulator includes one or more discontinuities therein. The micro-disc modulator may be a multi junction micro-disc modulator having two vertical p-n junctions with a single resonance frequency to achieve high-speed modulation and low-power consumption.Type: ApplicationFiled: July 8, 2014Publication date: January 14, 2016Inventors: Birendra Dutt, Ashok Kapoor, Weiwei Song, Raj Rajasekharan
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Publication number: 20080093636Abstract: A scalable device structure and process for forming a normally off JFET with 45 NM linewidths or less. The contacts to the source, drain and gate areas are formed by forming a layer of oxide of a thickness of less than 1000 angstroms, and, preferably 500 angstroms or less on top of the substrate. A nitride layer is formed on top of the oxide layer and holes are etched for the source, drain and gate contacts. A layer of polysilicon is then deposited so as to fill the holes and the polysilicon is polished back to planarize it flush with the nitride layer. The polysilicon contacts are then implanted with the types of impurities necessary for the channel type of the desired transistor and the impurities are driven into the semiconductor substrate below to form source, drain and gate regions.Type: ApplicationFiled: December 20, 2007Publication date: April 24, 2008Inventors: Madhukar Vora, Ashok Kapoor
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Publication number: 20070247213Abstract: An apparatus and method for manufacturing metal-oxide semiconductor (MOS) transistors that are operable at voltages below 1.5V, which MOS transistors are area efficient, and where the drive strength and leakage current of the MOS transistors is improved. The invention uses a dynamic threshold voltage control scheme that does not require a change to the existing MOS technology process. The invention provides a technique that controls the threshold voltage of the transistor. In the OFF state, the threshold voltage of the transistor is set high, keeping the transistor leakage to a small value. In the ON state, the threshold voltage is set to a low value, resulting in increased drive strength. The invention is particularly useful in MOS technology for both bulk and silicon on insulator (SOI) CMOS.Type: ApplicationFiled: April 19, 2007Publication date: October 25, 2007Inventor: Ashok KAPOOR
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Publication number: 20070229145Abstract: Metal-oxide semiconductor (MOS) transistors that are operable at voltages below 1.5V, that are area efficient, and that exhibit improved drive strength and leakage current that are disclosed. A dynamic threshold voltage control scheme is used that does not require a change to existing MOS technology processes. Threshold voltage of the transistor is controlled, such that in the Off state, the threshold voltage of the transistor is set high, keeping the transistor leakage to a small value. The advantages provided by apply to dynamic logic, as well as in the specific well separation imposed by design rules because well potential difference are lower than the supply voltage swing.Type: ApplicationFiled: March 9, 2007Publication date: October 4, 2007Inventors: Ashok Kapoor, Robert Strain, Reuven Marko
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Publication number: 20070126478Abstract: A method for using an inverter with a pair of complementary junction field effect transistors (CJFET) with a small linewidth is provided. The method includes having an input capacitance for said CJFET inverter to be less than the corresponding input capacitance of a CMOS inverter of similar linewidth. The CJFET operates at a power supply with a lesser value than the voltage drop across a forward-biased diode having a reduced switching power as compared to said CMOS inverter and having a propagation delay for said CJFET inverter that is at least comparable to the corresponding delay of said CMOS inverter.Type: ApplicationFiled: December 7, 2006Publication date: June 7, 2007Applicant: DSM Solutions Inc.Inventor: Ashok Kapoor
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Publication number: 20070096144Abstract: This invention describes a method of building complementary logic circuits using junction field effect transistors in silicon. This invention is ideally suited for deep submicron dimensions, preferably below 65 nm. The basis of this invention is a complementary Junction Field Effect Transistor which is operated in the enhancement mode. The speed-power performance of the JFETs becomes comparable with the CMOS devices at sub-70 nanometer dimensions. However, the maximum power supply voltage for the JFETs is still limited to below the built-in potential (a diode drop). To satisfy certain applications which require interface to an external circuit driven to higher voltage levels, this invention includes the structures and methods to build CMOS devices on the same substrate as the JFET devices.Type: ApplicationFiled: October 28, 2005Publication date: May 3, 2007Inventor: Ashok Kapoor
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Publication number: 20070069306Abstract: An apparatus and method of manufacture for metal-oxide semiconductor (MOS) transistors is disclosed. Devices in accordance with the invention are operable at voltages below 2V. The devices are area efficient, have improved drive strength, and have reduced leakage current. A dynamic threshold voltage control scheme comprised of a forward biased diode in parallel with a capacitor is used, implemented without changing the existing MOS technology process. This scheme controls the threshold voltage of each transistor. In the OFF state, the magnitude of the threshold voltage of the transistor increases, keeping the transistor leakage to a minimum. In the ON state, the magnitude of the threshold voltage decreases, resulting in increased drive strength. The invention is particularly useful in MOS technology for both bulk and silicon on insulator (SOI) CMOS. The use of reverse biasing of the well, in conjunction with the above construct to further decrease leakage in a MOS transistor, is also shown.Type: ApplicationFiled: September 19, 2006Publication date: March 29, 2007Inventors: Ashok Kapoor, Robert Strain, Reuven Marko
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Publication number: 20060202307Abstract: A bipolar transistor which has a base formed of a combination of shallow and deep acceptors species. Specifically, elements such as Indium, Tellurium, and Gallium are deep acceptors in silicon, and are appropriate for such an application, in combination with boron as the shallow acceptor. The use of a deep acceptor for doping the base of the transistor has the benefit of providing a doping species, which increases in ionization as the temperature rises. At elevated temperatures, the fraction of, for example, indium which is ionized increases and it results in an increased Gummel number, driving down the current gain. In other words, the enhancement of the Gummel number between room temperature and an elevated temperature compensates for the increase in the ratio of collector and base currents due to band gap narrowing effects. Thus, a zero temperature coefficient bipolar transistor is provided.Type: ApplicationFiled: March 11, 2005Publication date: September 14, 2006Inventor: Ashok Kapoor
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Publication number: 20060151842Abstract: An apparatus and method for the reduction of gate leakage in deep sub-micron metal oxide semiconductor (MOS) transistors, especially useful for those used in a cross coupled static random access memory (SRAM) cell, is disclosed. In accordance with the invention, the active element of the SRAM cell is used to reduce the voltage on the gate of its transistor without impacting the switching speed of the circuit. Because the load on the output of the inverter is fixed, a reduction in the gate current is optimized to minimize the impact on the switching waveform of the memory cell. An active element formed by two materials with different Fermi potentials is used as a rectifying junction or diode. The rectifying junction also has a large parallel leakage path, which allows a finite current flow when a signal of opposite polarity is applied across this device.Type: ApplicationFiled: April 19, 2005Publication date: July 13, 2006Inventor: Ashok Kapoor
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Publication number: 20060006479Abstract: In deep submicron memory arrays there is noted a relatively steady on current value and, therefore, threshold values of the transistors comprising the memory cell are reduced. This, in turn, results in an increase in the leakage current of the memory cell. With the use of an ever increasing number of memory cells leakage current must be controlled. A method and apparatus using a dynamic threshold voltage control scheme implemented with no more than minor changes to the existing MOS process technology is disclosed. The disclosed invention controls the threshold voltage of MOS transistors. Methods for enhancing the impact of the dynamic threshold control technology using this apparatus are also included. The invention is particularly useful for SRAM, DRAM, and NVM devices.Type: ApplicationFiled: December 29, 2004Publication date: January 12, 2006Inventor: Ashok Kapoor
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Publication number: 20060006923Abstract: An apparatus and method for manufacturing metal-oxide semiconductor (MOS) transistors that are operable at voltages below 1.5V, which MOS transistors are area efficient, and where the drive strength and leakage current of the MOS transistors is improved. The invention uses a dynamic threshold voltage control scheme that does not require a change to the existing MOS technology process. The invention provides a technique that controls the threshold voltage of the transistor. In the OFF state, the threshold voltage of the transistor is set high, keeping the transistor leakage to a small value. In the ON state, the threshold voltage is set to a low value, resulting in increased drive strength. The invention is particularly useful in MOS technology for both bulk and silicon on insulator (SOI) CMOS.Type: ApplicationFiled: January 4, 2005Publication date: January 12, 2006Inventor: Ashok Kapoor
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Publication number: 20050102167Abstract: This invention teaches a method of automating some of the tasks requiring continuous data collection at the patient bedside in a hospital in a manner which significantly reduces the chances of error in providing treatment. These tasks include provisioning of the IV pumps or other fluid infusion pumps, feed pumps, oxygen delivery systems, gathering, recording, storing, and analyzing signals from ECG machine or pulse oxymeter or any other medical device. This invention teaches the use of wireless transceiver modules which are connected to the data ports on the medical instrument to gather the data and transmit the data to a wireless access point. Protocols to identify the patient, care provider, medicine, equipment, and treatment are described. Use of an external means for verifying the identity of the medical device and the medicine is also described.Type: ApplicationFiled: September 30, 2004Publication date: May 12, 2005Inventor: Ashok Kapoor
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Patent number: 6121794Abstract: A CMOS buffer circuit isolates the low voltage CMOS logic gate from high voltage components on the chip and in the environment. The CMOS buffer circuit uses high voltage npn bipolar transistors with at least two P implants in the N- well serving as the base. The processing of the npn bipolar transistors uses an extra mask for the additional P implant, but advantageously does not require a thicker oxide growth. A CMOS output buffer circuit includes two high voltage npn bipolar transistors connected between the high voltage supply, e.g., 5.0 volts, and ground. The two bipolar transistors are driven by complementary signals generated by an inverter circuit or an emitter coupled logic circuit. The inverter circuit or emitter coupled logic circuit receive an input signal from the CMOS logic gate, which is connected between the low voltage supply, e.g., 1.8 to 3.3 volts, and ground.Type: GrantFiled: November 24, 1998Date of Patent: September 19, 2000Assignee: National Semiconductor CorporationInventor: Ashok Kapoor
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Patent number: 6005264Abstract: A microelectronic integrated circuit includes a semiconductor substrate, and a plurality of CMOS microelectronic devices formed on the substrate. Each device includes a hexagonal ANY element of a first conductivity type (PMOS or NMOS), and a hexagonal ALL element of a second conductivity type (NMOS or PMOS), the ANY and ALL elements each having a plurality of inputs and an output that are electrically interconnected respectively. The ANY element is basically an OR element, and the ALL element is basically an AND element. However, the power supply connections and the selection of conductivity type (NMOS or PMOS) for the ANY and ALL elements can be varied to provide the device as having a desired NAND, AND, NOR or OR configuration, in which the ANY element acts as a pull-up and the ALL element acts as a pull-down, or vice-versa.Type: GrantFiled: March 1, 1995Date of Patent: December 21, 1999Assignee: LSI Logic CorporationInventor: Ashok Kapoor
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Patent number: 5982659Abstract: A process which enables storage of more than two logic states in a memory cell. In one embodiment, a via is used to couple a diode between a word read line and a data read line. The via has a resistance which is set to one of a plurality of values at the time of manufacture. When the word read line is asserted, the voltage drop sustained across the via is indicative of the stored logic state. An analog-to-digital (A/D) converter is coupled to the data read line so as to sense the voltage drop and determine the state represented. Since the additional logic states may be used to represent additional information bits, this memory circuit increases the number of bits that may be stored per memory cell, thereby increasing the storage density and reducing the cost per bit.Type: GrantFiled: December 23, 1996Date of Patent: November 9, 1999Assignee: LSI Logic CorporationInventors: V. Swamy Irrinki, Thomas R. Wik, Raymond T. Leung, Ashok Kapoor, Alex Owens
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Patent number: 5867423Abstract: A circuit and method which enables storage of more than two logic states in a memory cell by selectively setting threshold voltages of transistors in a memory array according to the present invention. In one embodiment, a memory circuit includes an array of storage transistors. Each storage transistor has a gate connected to an associated read line. When a read line is asserted, the current which flows through a selected storage transistor is indicative of the stored logic state. The current through each transistor is individually selected by setting the threshold voltage of each storage transistor during manufacture. Different transistors in the array are configured with differing threshold voltages to thereby represent different storage states. An analog-to-digital (A/D) converter is coupled to the selected storage transistor so as to sense the current and determine the state represented.Type: GrantFiled: April 10, 1997Date of Patent: February 2, 1999Assignee: LSI Logic CorporationInventors: Ashok Kapoor, Alex Owens, Thomas R. Wik, Raymond T. Leung, V. Swamy Irrinki
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Patent number: 5847990Abstract: A memory circuit which enables storage of three logic states in a memory cell. Since the additional logic states may be used to represent additional information bits, this memory circuit increases the number of bits that may be stored per memory cell, thereby increasing the storage density and reducing the cost per bit. The disclosed memory circuit comprises an analog-to-digital converter coupled to detect a current through a transistor in a memory cell. The current is determined by the state of a tri-state flip-flop. By enabling the current to be detected as positive, negative, or zero, it becomes possible to represent more than one bit of information with the state of the flip-flop.Type: GrantFiled: December 23, 1996Date of Patent: December 8, 1998Assignee: LSI Logic CorporationInventors: V. Swamy Irrinki, Ashok Kapoor, Raymond T. Leung, Alex Owens, Thomas R. Wik
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Patent number: 5808932Abstract: A memory circuit which enables storage of more than two logic states in a memory cell. Since the additional logic states may be used to represent additional information bits, this memory circuit increases the number of bits that may be stored per memory cell, thereby increasing the storage density and reducing the cost per bit. The disclosed memory circuit comprises an analog-to-digital converter coupled to detect a current through a transistor in a memory cell. The current is determined by a charge stored on the transistor's gate. By enabling the current to be detected in discrete increments, it becomes possible to represent more than one bit of information with the charge stored in the memory cell. Usage of additional increments necessitates more precise storage and detection circuitry. In one embodiment, the storage circuitry uses feedback to obtain a greater logic state retrieval accuracy.Type: GrantFiled: December 23, 1996Date of Patent: September 15, 1998Assignee: LSI Logic CorporationInventors: V. Swamy Irrinki, Ashok Kapoor, Raymond T. Leung, Alex Owens, Thomas R. Wik
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Patent number: 5784328Abstract: A DRAM memory array including a temperature sensor for adjusting a refresh rate depending upon temperature. The DRAM memory array includes a plurality of memory cells, each configured to allow storage and retrieval of more than two discrete memory states. A refresh circuit is coupled to the memory array for periodically refreshing the discrete storage state of each memory cell. The temperature sensor is situated on the same semiconductor die upon which the memory array is fabricated, and generates a signal indicative of the temperature of the semiconductor die. A control circuit receives the signal from the temperature sensor and responsively generates a refresh rate signal which is provided to control the refresh rate of the refresh circuit. In one specific implementation, a ROM look-up table is coupled to the control circuit and includes a plurality of entries which indicate the desired refresh rates for particular temperatures.Type: GrantFiled: December 23, 1996Date of Patent: July 21, 1998Assignee: LSI Logic CorporationInventors: V. Swamy Irrinki, Ashok Kapoor, Raymond Leung, Alex Owens, Thomas R. Wik