Patents Assigned to SuVolta, Inc.
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Patent number: 8819603Abstract: A circuit can include a plurality of storage circuits, each having a pair of first conductivity type transistor having sources commonly connected to a first node, and gates and drains cross-coupled between first and second storage node; and a pair of second conductivity type transistor having sources commonly connected to a second node, and gates and drains cross-coupled between the first and second storage node; wherein each of the second conductivity type transistors comprises a screening region of the first conductivity type formed below the channel region and has a predetermined minimum dopant concentration.Type: GrantFiled: December 14, 2012Date of Patent: August 26, 2014Assignee: Suvolta, Inc.Inventors: Lawrence T. Clark, Samuel Leshner
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Patent number: 8811068Abstract: An integrated circuit can include SRAM cells, with pull-up transistors, pull-down transistors, and pass-gate transistors having a screening region positioned a distance below the gate and separated from the gate by a semiconductor layer. The screening region has a concentration of screening region dopants, the concentration of screening region dopants being higher than a concentration of dopants in the semiconductor layer. The screening region can provide an enhanced body coefficient for the pull-up transistors to increase a read static noise margin of the SRAM cell when a bias voltage is applied to the screening region. Related methods are also disclosed.Type: GrantFiled: May 14, 2012Date of Patent: August 19, 2014Assignee: Suvolta, Inc.Inventors: Lawrence T. Clark, Scott E. Thompson, Richard S. Roy, Robert Rogenmoser, Damodar R. Thummalapally
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Patent number: 8806395Abstract: Porting a first integrated circuit design targeted for implementation in a first semiconductor manufacturing process, and implementing a second circuit design in a second semiconductor manufacturing process wherein the electrical performance of the second integrated circuit meets or exceeds the requirements of the first integrated circuit design even if the threshold voltage targets of the second integrated circuit design are different from those of the first integrated circuit design; and wherein physical layouts, and in particular the gate-widths and gate-lengths of the transistors, of the first and second integrated circuit designs are the same or substantially the same. The second integrated circuit design, when fabricated in the second semiconductor manufacturing process and then operated, experiences less off-state transistor leakage current than does the first integrated circuit design, when fabricated in the first semiconductor manufacturing process, and then operated.Type: GrantFiled: February 3, 2014Date of Patent: August 12, 2014Assignee: SuVolta, Inc.Inventors: Lawrence T. Clark, Scott E. Thompson, Richard S. Roy, Samuel Leshner
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Patent number: 8796048Abstract: The present disclosure provides methods and structures for measurement, control, and monitoring the thickness of thin film layers formed as part of a semiconductor manufacturing process. The methods and structures presented provide the capability to measure and monitor the thickness of the thin film using trench line structures. In certain embodiments, the thin film thickness measurement system can be integrated with thin film growth and control software, providing automated process control (APC) or statistical process control (SPC) capability by measuring and monitoring the thin film thickness during manufacturing. Methods for measuring the thickness of thin films can be important to the fabrication of integrated circuits because the thickness and uniformity of the thin film can determine electrical characteristics of the transistors being fabricated.Type: GrantFiled: May 11, 2012Date of Patent: August 5, 2014Assignee: Suvolta, Inc.Inventors: Scott E. Thompson, Pushkar Ranade, Lance Scudder, Charles Stager
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Patent number: 8778786Abstract: Silicon loss prevention in a substrate during transistor device element manufacture is achieved by limiting a number of photoresist mask and chemical oxide layer stripping opportunities during the fabrication process. This can be achieved through the use of a protective layer that remains on the substrate during formation and stripping of photoresist masks used in identifying the implant areas into the substrate. In addition, undesirable reworking steps due to photoresist mask misalignment are eliminated or otherwise have no effect on consuming silicon from the substrate during fabrication of device elements. In this manner, device elements with the same operating characteristics and performance can be consistently made from lot to lot.Type: GrantFiled: May 29, 2012Date of Patent: July 15, 2014Assignee: SuVolta, Inc.Inventors: Lance Scudder, Pushkar Ranade, Dalong Zhao, Teymur Bakhishev, Urupattur C. Sridharan, Taiji Ema, Toshifumi Mori, Mitsuaki Hori, Junji Oh, Kazushi Fujita, Yasunobu Torii
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Patent number: 8759872Abstract: A structure and method of fabrication thereof relate to a Deeply Depleted Channel (DDC) design, allowing CMOS based devices to have a reduced ?VT compared to conventional bulk CMOS and can allow the threshold voltage VT of FETs having dopants in the channel region to be set much more precisely. A novel dopant profile indicative of a distinctive notch enables tuning of the VT setting within a precise range. This VT set range may be extended by appropriate selection of metals so that a very wide range of VT settings is accommodated on the die. The DDC design also can have a strong body effect compared to conventional bulk CMOS transistors, which can allow for significant dynamic control of power consumption in DDC transistors. The result is the ability to independently control VT (with a low ?VT) and VDD, so that the body bias can be tuned separately from VT for a given device.Type: GrantFiled: December 17, 2010Date of Patent: June 24, 2014Assignee: SuVolta, Inc.Inventors: Reza Arghavani, Pushkar Ranade, Lucian Shifren, Scott E. Thompson, Catherine de Villeneuve
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Publication number: 20140167157Abstract: A planar transistor with improved performance has a source and a drain on a semiconductor substrate that includes a substantially undoped channel extending between the source and the drain. A gate is positioned over the substantially undoped channel on the substrate. Implanted source/drain extensions contact the source and the drain, with the implanted source/drain extensions having a dopant concentration of less than about 1×1019 atoms/cm3, or alternatively, less than one-quarter the dopant concentration of the source and the drain.Type: ApplicationFiled: February 24, 2014Publication date: June 19, 2014Applicant: SuVolta, Inc.Inventors: Pushkar Ranade, Lucian Shifren, Sachin R. Sonkusale
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Patent number: 8748270Abstract: An analog transistor useful for low noise applications or for electrical circuits benefiting from tight control of threshold voltages and electrical characteristics is described. The analog transistor includes a substantially undoped channel positioned under a gate dielectric between a source and a drain with the undoped channel not being subjected to contaminating threshold voltage implants or halo implants. The channel is supported on a screen layer doped to have an average dopant density at least five times as great as the average dopant density of the substantially undoped channel which, in turn, is supported by a doped well having an average dopant density at least twice the average dopant density of the substantially undoped channel.Type: GrantFiled: July 20, 2012Date of Patent: June 10, 2014Assignee: SuVolta, Inc.Inventors: Lucian Shifren, Scott E. Thompson, Paul E. Gregory
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Patent number: 8748986Abstract: Structures and methods of fabrication thereof related to an improved semiconductor on insulator (SOI) transistor formed on an SOI substrate. The improved SOI transistor includes a substantially undoped channel extending between the source and the drain, an optional threshold voltage set region positioned below the substantially undoped channel, and a screening region positioned below the threshold voltage set region. The threshold voltage of the improved SOI transistor can be adjusted without halo implants or threshold voltage implants into the channel, using the position and/or dopant concentration of the screening region and/or the threshold voltage set region.Type: GrantFiled: July 26, 2012Date of Patent: June 10, 2014Assignee: Suvolta, Inc.Inventors: Lucian Shifren, Pushkar Ranade
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Patent number: 8735987Abstract: A semiconductor device includes a substrate having a semiconducting surface having formed therein a first active region and a second active region, where the first active region consists of a substantially undoped layer at the surface and a highly doped screening layer of a first conductivity type beneath the first substantially undoped layer, and the second active region consists of a second substantially undoped layer at the surface and a second highly doped screening layer of a second conductivity type beneath the second substantially undoped layer. The semiconductor device also includes a gate stack formed in each of the first active region and the second active region consists of at least one gate dielectric layer and a layer of a metal, where the metal has a workfunction that is substantially midgap with respect to the semiconducting surface.Type: GrantFiled: June 6, 2012Date of Patent: May 27, 2014Assignee: Suvolta, Inc.Inventors: Thomas Hoffmann, Scott E. Thompson, Pushkar Ranade
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Publication number: 20140119099Abstract: A dynamic random access memory (DRAM) can include at least one DRAM cell array, comprising a plurality of DRAM cells, each including a storage capacitor and access transistor; a body bias control circuit configured to generate body bias voltage from a bias supply voltage, the body bias voltage being different from power supply voltages of the DRAM; and peripheral circuits formed in the same substrate as the at least one DRAM array, the peripheral circuits comprising deeply depleted channel (DDC) transistors having bodies coupled to receive the body bias voltage, each DDC transistor having a screening region of a first conductivity type formed below a substantially undoped channel region.Type: ApplicationFiled: October 31, 2013Publication date: May 1, 2014Applicant: Suvolta, Inc.Inventors: Lawrence T. Clark, Lucian Shifren, Richard S. Roy
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Patent number: 8713511Abstract: An integrated circuit having at least one array of circuit cells, each circuit cell having a plurality of transistors each performing a specified function, the transistors having predefined performance parameter margins for the specified function, the circuit cells designed by providing at least one operating condition for the circuit cell; providing a value of sigma over a predefined range; determining for each transistor, at least one variable transistor characteristic, which is defined by a semiconductor process that results in transistors having such transistor characteristics; providing an array of instances based upon the value of the sigma and using a design of experiments factorial calculation; providing a metric of interest by which to deter-nine pass/fail instances; extracting individual pass/fail instances for the metric of interest; and determining a yield for the array of circuit cells for the targeted operating condition.Type: GrantFiled: September 17, 2012Date of Patent: April 29, 2014Assignee: SuVolta, Inc.Inventors: Lawrence T. Clark, Samuel Leshner
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Patent number: 8686511Abstract: A planar transistor with improved performance has a source and a drain on a semiconductor substrate that includes a substantially undoped channel extending between the source and the drain. A gate is positioned over the substantially undoped channel on the substrate. Implanted source/drain extensions contact the source and the drain, with the implanted source/drain extensions having a dopant concentration of less than about 1×1019 atoms/cm3?, or alternatively, less than one-quarter the dopant concentration of the source and the drain.Type: GrantFiled: September 18, 2013Date of Patent: April 1, 2014Assignee: SuVolta, Inc.Inventors: Pushkar Ranade, Lucian Shifren, Sachin R. Sonkusale
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Publication number: 20140084385Abstract: A semiconductor transistor structure fabricated on a silicon substrate effective to set a threshold voltage, control short channel effects, and control against excessive junction leakage may include a transistor gate having a source and drain structure. A highly doped screening region lies is embedded a vertical distance down from the surface of the substrate. The highly doped screening region is separated from the surface of the substrate by way of a substantially undoped channel layer which may be epitaxially formed. The source/drain structure may include a source/drain extension region which may be raised above the surface of the substrate. The screening region is preferably positioned to be located at or just below the interface between the source/drain region and source/drain extension portion. The transistor gate may be formed below a surface level of the silicon substrate and either above or below the heavily doped portion of the source/drain structure.Type: ApplicationFiled: September 5, 2013Publication date: March 27, 2014Applicant: SuVolta, Inc.Inventors: Thomas Hoffmann, Lucian Shifren, Scott E. Thompson, Pushkar Ranade, Jing Wang, Paul E. Gregory, Sachin R. Sonkusale, Lance Scudder, Dalong Zhao, Teymur Bakhishev, Yujie Liu, Lingquan Wang, Weimin Zhang, Sameer Pradhan, Michael Duane, Sung Hwan Kim
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Publication number: 20140077312Abstract: Some structures and methods to reduce power consumption in devices can be implemented largely by reusing existing bulk CMOS process flows and manufacturing technology, allowing the semiconductor industry as well as the broader electronics industry to avoid a costly and risky switch to alternative technologies. Some of the structures and methods relate to a Deeply Depleted Channel (DDC) design, allowing CMOS based devices to have a reduced ?VT compared to conventional bulk CMOS and can allow the threshold voltage VT of FETs having dopants in the channel region to be set much more precisely. The DDC design also can have a strong body effect compared to conventional bulk CMOS transistors, which can allow for significant dynamic control of power consumption in DDC transistors. Additional structures, configurations, and methods presented herein can be used alone or in conjunction with the DDC to yield additional and different benefits.Type: ApplicationFiled: November 18, 2013Publication date: March 20, 2014Applicant: SuVolta, Inc.Inventors: Scott E. Thompson, Damodar R. Thummalapally
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Patent number: 8653604Abstract: Multiple transistor types are formed in a common epitaxial layer by differential out-diffusion from a doped underlayer. Differential out-diffusion affects the thickness of a FET channel, the doping concentration in the FET channel, and distance between the gate dielectric layer and the doped underlayer. Differential out-diffusion may be achieved by differentially applying a dopant migration suppressor such as carbon; differentially doping the underlayer with two or more dopants having the same conductivity type but different diffusivities; and/or differentially applying thermal energy.Type: GrantFiled: September 21, 2012Date of Patent: February 18, 2014Assignee: SuVolta, Inc.Inventors: Thomas Hoffmann, Pushkar Ranade, Lucian Shifren, Scott E. Thompson
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Publication number: 20140035060Abstract: A semiconductor structure includes a first PMOS transistor element having a gate region with a first gate metal associated with a PMOS work function and a first NMOS transistor element having a gate region with a second metal associated with a NMOS work function. The first PMOS transistor element and the first NMOS transistor element form a first CMOS device. The semiconductor structure also includes a second PMOS transistor that is formed in part by concurrent deposition with the first NMOS transistor element of the second metal associated with a NMOS work function to form a second CMOS device with different operating characteristics than the first CMOS device.Type: ApplicationFiled: October 4, 2013Publication date: February 6, 2014Applicant: SuVolta, Inc.Inventors: Lucian Shifren, Pushkar Ranade, Sachin R. Sonkusale
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Publication number: 20140038386Abstract: A method for fabricating field effect transistors using carbon doped silicon layers to substantially reduce the diffusion of a doped screen layer formed below a substantially undoped channel layer includes forming an in-situ epitaxial carbon doped silicon substrate that is doped to form the screen layer in the carbon doped silicon substrate and forming the substantially undoped silicon layer above the carbon doped silicon substrate. The method may include implanting carbon below the screen layer and forming a thin layer of in-situ epitaxial carbon doped silicon above the screen layer. The screen layer may be formed either in a silicon substrate layer or the carbon doped silicon substrate.Type: ApplicationFiled: October 4, 2013Publication date: February 6, 2014Applicant: SuVolta, Inc.Inventors: Lance S. Scudder, Pushkar Ranade, Charles Stager, Urupattur C. Sridharan, Dalong Zhao
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Patent number: 8645878Abstract: Porting a first integrated circuit design targeted for implementation in a first semiconductor manufacturing process, and implementing a second circuit design in a second semiconductor manufacturing process wherein the electrical performance of the second integrated circuit meets or exceeds the requirements of the first integrated circuit design even if the threshold voltage targets of the second integrated circuit design are different from those of the first integrated circuit design; and wherein physical layouts, and in particular the gate-widths and gate-lengths of the transistors, of the first and second integrated circuit designs are the same or substantially the same. The second integrated circuit design, when fabricated in the second semiconductor manufacturing process and then operated, experiences less off-state transistor leakage current than does the first integrated circuit design, when fabricated in the first semiconductor manufacturing process, and then operated.Type: GrantFiled: August 22, 2012Date of Patent: February 4, 2014Assignee: SuVolta, Inc.Inventors: Lawrence T. Clark, Scott E. Thompson, Richard S. Roy, Samuel Leshner
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Patent number: 8637955Abstract: A semiconductor structure is formed with a NFET device and a PFET device. The NFET device is formed by masking the PFET device regions of a substrate, forming a screen layer through epitaxial growth and in-situ doping, and forming an undoped channel layer on the screen layer through epitaxial growth. The PFET device is similarly formed by masking the NFET regions of a substrate, forming a screen layer through epitaxial growth and in-situ doping, and forming an undoped channel layer on the screen layer through epitaxial growth. An isolation region is formed between the NFET and the PFET device areas to remove any facets occurring during the separate epitaxial growth phases. By forming the screen layer through in-situ doped epitaxial growth, a reduction in junction leakage is achieved versus forming the screen layer using ion, implantation.Type: GrantFiled: August 31, 2012Date of Patent: January 28, 2014Assignee: SuVolta, Inc.Inventors: Lingquan Wang, Teymur Bakhishev, Dalong Zhao, Pushkar Ranade, Sameer Pradhan, Thomas Hoffmann, Lucian Shifren, Lance Scudder