Patents by Inventor Vishnu K
Vishnu K 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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Publication number: 20110241083Abstract: Transistors (21, 41) employing floating buried layers may be susceptible to noise coupling into the floating buried layers. In IGFETS this is reduced or eliminated by providing a normally-ON switch (80, 80?) coupling the buried layer (102, 142, 172, 202) and the IGFET source (22, 42) or drain (24, 44). When the transistor (71, 91) is OFF, this clamps the buried layer voltage and substantially prevents noise coupling thereto. When the drain-source voltage VDS exceeds the switch's (80, 80?) threshold voltage Vt, it turns OFF, allowing the buried layer (102, 142, 172, 202) to float, and thereby resume normal transistor action without degrading the breakdown voltage or ON-resistance. In a preferred embodiment, a normally-ON lateral JFET (801, 801?, 801-1, 801-2, 801-3) conveniently provides this switching function.Type: ApplicationFiled: March 30, 2010Publication date: October 6, 2011Applicant: FREESCALE SEMICONDUCTOR, INC.Inventors: Vishnu K. Khemka, Tahir A. Khan, Weixiao Huang, Ronghua Zhu
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Publication number: 20110206332Abstract: A waveguide and resonator are formed on a lower cladding of a thermo optic device, each having a formation height that is substantially equal. Thereafter, the formation height of the waveguide is attenuated. In this manner, the aspect ratio as between the waveguide and resonator in an area where the waveguide and resonator front or face one another decreases (in comparison to the prior art) thereby restoring the synchronicity between the waveguide and the grating and allowing higher bandwidth configurations to be used. The waveguide attenuation is achieved by photomasking and etching the waveguide after the resonator and waveguide are formed. In one embodiment the photomasking and etching is performed after deposition of the upper cladding. In another, it is performed before the deposition. Thermo optic devices, thermo optic packages and fiber optic systems having these waveguides are also taught.Type: ApplicationFiled: May 2, 2011Publication date: August 25, 2011Inventors: Guy T. Blalock, Howard E. Rhodes, Vishnu K. Agarwal, Gurtel Singh Sandhu, James S. Foresi, Jean-Francois Viens, Dale G. Fried
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Publication number: 20110101425Abstract: Methods and apparatus are provided for fabricating a semiconductor device structure. The semiconductor device structure comprises a buried region having a first conductivity type, a first region having a second conductivity type overlying the buried region, a source region having the first conductivity type overlying the first region, and a drain region having the first conductivity type overlying the first region. The semiconductor device structure further comprises a second region having the first conductivity type overlying the buried region, the second region abutting the buried region to form an electrical contact with the buried region, and a first resistance configured electrically in series with the second region and the buried region. The combined series resistance of the first resistance and the second region is greater than a resistance of the buried region.Type: ApplicationFiled: October 29, 2009Publication date: May 5, 2011Applicant: FREESCALE SEMICONDUCTOR, INC.Inventors: Bernhard H. Grote, Vishnu K. Khemka, Tahir A. Khan, Weixiao Huang, Ronghua Zhu
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Patent number: 7936955Abstract: A waveguide and resonator are formed on a lower cladding of a thermo optic device, each having a formation height that is substantially equal. Thereafter, the formation height of the waveguide is attenuated. In this manner, the aspect ratio as between the waveguide and resonator in an area where the waveguide and resonator front or face one another decreases (in comparison to the prior art) thereby restoring the synchronicity between the waveguide and the grating and allowing higher bandwidth configurations to be used. The waveguide attenuation is achieved by photomasking and etching the waveguide after the resonator and waveguide are formed. In one embodiment the photomasking and etching is performed after deposition of the upper cladding. In another, it is performed before the deposition. Thermo optic devices, thermo optic packages and fiber optic systems having these waveguides are also taught.Type: GrantFiled: May 14, 2010Date of Patent: May 3, 2011Assignee: Micron Technology, Inc.Inventors: Guy T. Blalock, Howard E. Rhodes, Vishnu K. Agarwal, Gurtej Singh Sandhu, James S. Foresi, Jean-Francois Viens, Dale G. Fried
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Publication number: 20110024813Abstract: Methods and apparatus are described for MOS capacitors (MOS CAPs). The apparatus comprises a substrate having Ohmically coupled N and P semiconductor regions covered by a dielectric. A conductive electrode overlies the dielectric above these N and P regions. Use of the Ohmically coupled N and P regions substantially reduces the variation of capacitance with applied voltage associated with ordinary MOS CAPs. When these N and P regions have unequal doping, the capacitance variation may still be substantially compensated by adjusting the properties of the dielectric above the N and P regions and/or relative areas of the N and P regions or both. Accordingly, such MOS CAPS may be more easily integrated with other semiconductor devices with minimal or no disturbance to the established integrated circuit (IC) manufacturing process and without significantly increasing the occupied area beyond that required for a conventional MOS CAP.Type: ApplicationFiled: October 12, 2010Publication date: February 3, 2011Applicant: FREESCALE SEMICONDUCTOR, INC.Inventors: Tahir A. Khan, Amitava Bose, Vishnu K. Khemka, Ronghua Zhu
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Patent number: 7851889Abstract: Apparatus and methods are provided for fabricating semiconductor devices with reduced bipolar effects. One apparatus includes a semiconductor body (120) including a surface and a transistor source (300) located in the semiconductor body proximate the surface, and the transistor source includes an area (310) of alternating conductivity regions (3110, 3120). Another apparatus includes a semiconductor body (120) including a first conductivity and a transistor source (500) located in the semiconductor body. The transistor source includes multiple regions (5120) including a second conductivity, wherein the regions and the semiconductor body form an area (510) of alternating regions of the first and second conductivities. One method includes implanting a semiconductor well (120) including a first conductivity in a substrate (110) and implanting a plurality of doped regions (5120) comprising a second conductivity in the semiconductor well.Type: GrantFiled: April 30, 2007Date of Patent: December 14, 2010Assignee: Freescale Semiconductor, Inc.Inventors: Ronghua Zhu, Amitava Bose, Vishnu K. Khemka, Todd C. Roggenbauer
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Patent number: 7851857Abstract: A dual current path LDMOSFET transistor (40) is provided which includes a substrate (400), a graded buried layer (401), an epitaxial drift region (404) in which a drain region (416) is formed, a first well region (406) in which a source region (412) is formed, a gate electrode (420) formed adjacent to the source region (412) to define a first channel region (107), and a current routing structure that includes a buried RESURF layer (408) in ohmic contact with a second well region (414) formed in a predetermined upper region of the epitaxial layer (404) so as to be completely covered by the gate electrode (420), the current routing structure being spaced apart from the first well region (406) and from the drain region (416) on at least a side of the drain region to delineate separate current paths from the source region and through the epitaxial layer.Type: GrantFiled: July 30, 2008Date of Patent: December 14, 2010Assignee: Freescale Semiconductor, Inc.Inventors: Yue Fu, Ronghua Zhu, Vishnu K. Khemka, Amitava Bose, Todd C. Roggenbauer
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Patent number: 7838383Abstract: Method (200) and apparatus (30, 50-53) are described for MOS capacitors (MOS CAPs). The apparatus (30, 50-53) comprises a substrate (31) having Ohmically coupled N and P semiconductor regions (32, 34; 54, 56; 92, 94) covered by a dielectric (35, 57, 95). A conductive electrode (36, 58, 96) overlies the dielectric (35, 57, 95) above these N and P regions (32, 34; 54, 56; 92, 94). Use of the Ohmically coupled N and P regions (32, 34; 54, 56; 92, 94) substantially reduces the variation (40, 64, 70, 80) of capacitance with applied voltage associated with ordinary MOS CAPs. When these N and P regions (32, 34; 54, 56; 92, 94) have unequal doping, the capacitance variation (40, 64, 70, 80) may still be substantially compensated by adjusting the properties of the dielectric (57, 95) above the N and P regions (54, 56; 92, 94) and/or relative areas of the N and P regions (54, 56; 92, 94) or both.Type: GrantFiled: January 4, 2008Date of Patent: November 23, 2010Assignee: Freescale Semiconductor, Inc.Inventors: Tahir A. Khan, Amitava Bose, Vishnu K. Khemka, Ronghua Zhu
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Publication number: 20100290265Abstract: Apparatus and systems may comprise electrode structures that include two or more dissimilar and abutting metal layers on a surface, some of the electrode structures separated by a gap; and a polymer-based ferroelectric layer overlying and directly abutting some of the electrode structures. Methods may comprise actions to form and operate the apparatus and systems. Additional apparatus, systems, and methods are disclosed.Type: ApplicationFiled: July 30, 2010Publication date: November 18, 2010Inventors: Vishnu K. Agarwal, Howard E. Rhodes
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Patent number: 7820519Abstract: A process of forming an electronic device can include providing a semiconductor-on-insulator substrate including a substrate, a first semiconductor layer, and a buried insulating layer lying between the first semiconductor layer and the substrate. The process can also include forming a field isolation region within the semiconductor layer, and forming an opening extending through the semiconductor layer and the buried insulating layer to expose the substrate. The process can further include forming a conductive structure within the opening, wherein the conductive structure abuts the substrate.Type: GrantFiled: November 3, 2006Date of Patent: October 26, 2010Assignee: Freescale Semiconductor, Inc.Inventors: Todd C. Roggenbauer, Vishnu K. Khemka, Ronghua Zhu, Amitava Bose, Paul Hui, Xiaoqiu Huang, Van Wong
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Patent number: 7791161Abstract: Structure and method are provided for semiconductor devices. The devices include trenches filled with highly doped polycrystalline semiconductor, extending from the surface into the body of the device for, among other things: (i) reducing substrate current injection, (ii) reducing ON-resistance and/or (iii) reducing thermal impedance to the substrate. For isolated LDMOS devices, the resistance between the lateral isolation wall (tied to the source) and the buried layer is reduced, thereby reducing substrate injection current. When placed in the drain of a lateral device or in the collector of a vertical device, the poly-filled trench effectively enlarges the drain or collector region, thereby lowering the ON-resistance. For devices formed on an oxide isolation layer, the poly-filled trench desirably penetrates this isolation layer thereby improving thermal conduction from the active regions to the substrate. The poly filled trenches are conveniently formed by etch and refill.Type: GrantFiled: August 25, 2005Date of Patent: September 7, 2010Assignee: Freescale Semiconductor, Inc.Inventors: Ronghua Zhu, Vishnu K. Khemka, Amitava Bose
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Publication number: 20100220958Abstract: A waveguide and resonator are formed on a lower cladding of a thermo optic device, each having a formation height that is substantially equal. Thereafter, the formation height of the waveguide is attenuated. In this manner, the aspect ratio as between the waveguide and resonator in an area where the waveguide and resonator front or face one another decreases (in comparison to the prior art) thereby restoring the synchronicity between the waveguide and the grating and allowing higher bandwidth configurations to be used. The waveguide attenuation is achieved by photomasking and etching the waveguide after the resonator and waveguide are formed. In one embodiment the photomasking and etching is performed after deposition of the upper cladding. In another, it is performed before the deposition. Thermo optic devices, thermo optic packages and fiber optic systems having these waveguides are also taught.Type: ApplicationFiled: May 14, 2010Publication date: September 2, 2010Inventors: Guy T. Blalock, Howard E. Rhodes, Vishnu K. Agarwal, Gurtej Singh Sandhu, James S. Foresi, Jean-Francois Viens, Dale G. Fried
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Patent number: 7777257Abstract: A low leakage bipolar Schottky diode (20, 40, 87) is formed by parallel lightly doped N (32, 52, 103) and P (22, 42, 100) regions adapted to form superjunction regions. First ends of the P regions (22, 42, 100) are terminated by P+ layers (21, 41, 121) and second, opposed ends of the N regions (32, 52, 103) are terminated by N+ layers (31, 51, 131). Silicide layers (24, 34, 44, 54, 134, 124) are provided in contact with both ends of the parallel N and P regions (22, 32, 42, 52, 100, 103), thereby forming at the first end ohmic contacts (28, 48) with the P+ regions (21, 41, 121) and Schottky contacts (37, 57) with the N regions 32, 52, 103) and at the second, opposite end, ohmic contacts (38, 58) with the N+ regions (31, 51, 131) and Schottky contacts (27, 47) with the P regions (22, 42, 100). When forward biased current flows in both N (32, 52) and P (22, 42) regions thereby reducing the forward drop.Type: GrantFiled: February 14, 2007Date of Patent: August 17, 2010Assignee: Freescale Semiconductor, Inc.Inventors: Vishnu K. Khemka, Amitava Bose, Todd C. Roggenbauer, Ronghua Zhu
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Patent number: 7768049Abstract: Integrated memory circuits, key components in thousands of electronic and computer products, have been made using ferroelectric materials, which offer faster write cycles and lower power requirements than some other materials. However, the present inventors have recognized, for example, that conventional techniques for working with the polymers produce polymer layers with thickness variations that compromise performance and manufacturing yield. Accordingly, the present inventors devised unique methods and structures for polymer-based ferroelectric memories. One exemplary method entails forming an insulative layer on a substrate, forming two or more first conductive structures, with at least two of the first conductive structures separated by a gap, forming a gap-filling structure within the gap, and forming a polymer-based ferroelectric layer over the gap-filling structure and the first conductive structures. In some embodiments, the gap-filling structure is a polymer, a spin-on-glass, or a flow-fill oxide.Type: GrantFiled: August 30, 2005Date of Patent: August 3, 2010Assignee: Micron Technology, Inc.Inventors: Vishnu K. Agarwal, Howard E. Rhodes
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Patent number: 7763937Abstract: Methods and apparatus are provided for semiconductor device (60, 95, 100, 106). The semiconductor device (60, 95, 100, 106), comprises a first region (64, 70) of a first conductivity type extending to a first surface (80), a second region (66) of a second, opposite, conductivity type forming with the first region (70) a first PN junction (65) extending to the first surface (80), a contact region (68) of the second conductivity type in the second region (66) at the first surface (80) and spaced apart from the first PN junction (65) by a first distance (LDS), and a third region (82, 96-98, 108) of the first conductivity type and of a second length (LBR), underlying the second region (66) and forming a second PN junction (63) therewith spaced apart from the first surface (80) and located closer to the first PN junction (65) than to the contact region (68). The breakdown voltage is enhanced without degrading other useful properties of the device (60, 95, 100, 106).Type: GrantFiled: November 15, 2006Date of Patent: July 27, 2010Assignee: Freescale Semiconductor, Inc.Inventors: Vishnu K. Khemka, Amitava Bose, Todd C. Roggenbauer, Ronghua Zhu
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Patent number: 7723204Abstract: A microelectronic assembly and a method for constructing a microelectronic assembly are provided. The microelectronic assembly may include a semiconductor substrate with an isolation trench (62) formed therein. The isolation trench (62) may have first and second opposing inner walls (74, 76) and a floor (78). First and second conductive plates (106) may be formed over the first and second opposing inner walls (74, 76) of the isolation trench (62) respectively such that there is a gap (90) between the first and second conductive plates (106). First and second semiconductor devices (114) may be formed in the semiconductor substrate on opposing sides of the isolation trench (62). The method may include forming a trench (62) in a semiconductor substrate, forming first and second conductive plates (106) within the trench, and forming first and second semiconductor devices (114) in the semiconductor substrate on opposing sides of the trench (62).Type: GrantFiled: March 27, 2006Date of Patent: May 25, 2010Assignee: Freescale Semiconductor, Inc.Inventors: Vishnu K. Khemka, Amitava Bose, Todd C. Roggenbauer, Ronghua Zhu
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Patent number: 7720341Abstract: A waveguide and resonator are formed on a lower cladding of a thermo optic device, each having a formation height that is substantially equal. Thereafter, the formation height of the waveguide is attenuated. In this manner, the aspect ratio as between the waveguide and resonator in an area where the waveguide and resonator front or face one another decreases (in comparison to the prior art) thereby restoring the synchronicity between the waveguide and the grating and allowing higher bandwidth configurations to be used. The waveguide attenuation is achieved by photomasking and etching the waveguide after the resonator and waveguide are formed. In one embodiment the photomasking and etching is performed after deposition of the upper cladding. In another, it is performed before the deposition. Thermo optic devices, thermo optic packages and fiber optic systems having these waveguides are also taught.Type: GrantFiled: March 13, 2008Date of Patent: May 18, 2010Assignee: Micron Technology, Inc.Inventors: Guy T. Blalock, Howard E. Rhodes, Vishnu K. Agarwal, Gurtej Singh Sandhu, James S. Foresi, Jean-Francois Viens, Dale G. Fried
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Publication number: 20100025756Abstract: A dual current path LDMOSFET transistor (40) is provided which includes a substrate (400), a graded buried layer (401), an epitaxial drift region (404) in which a drain region (416) is formed, a first well region (406) in which a source region (412) is formed, a gate electrode (420) formed adjacent to the source region (412) to define a first channel region (107), and a current routing structure that includes a buried RESURF layer (408) in ohmic contact with a second well region (414) formed in a predetermined upper region of the epitaxial layer (404) so as to be completely covered by the gate electrode (420), the current routing structure being spaced apart from the first well region (406) and from the drain region (416) on at least a side of the drain region to delineate separate current paths from the source region and through the epitaxial layer.Type: ApplicationFiled: July 30, 2008Publication date: February 4, 2010Inventors: Yue Fu, Ronghua Zhu, Vishnu K. Khemka, Amitava Bose, Todd C. Roggenbauer
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Publication number: 20090174030Abstract: Method (200) and apparatus (30, 50-53) are described for MOS capacitors (MOS CAPs). The apparatus (30, 50-53) comprises a substrate (31) having Ohmically coupled N and P semiconductor regions (32, 34; 54, 56; 92, 94) covered by a dielectric (35, 57, 95). A conductive electrode (36, 58, 96) overlies the dielectric (35, 57, 95) above these N and P regions (32, 34; 54, 56; 92, 94). Use of the Ohmically coupled N and P regions (32, 34; 54, 56; 92, 94) substantially reduces the variation (40, 64, 70, 80) of capacitance with applied voltage associated with ordinary MOS CAPs. When these N and P regions (32, 34; 54, 56; 92, 94) have unequal doping, the capacitance variation (40, 64, 70, 80) may still be substantially compensated by adjusting the properties of the dielectric (57, 95) above the N and P regions (54, 56; 92, 94) and/or relative areas of the N and P regions (54, 56; 92, 94) or both.Type: ApplicationFiled: January 4, 2008Publication date: July 9, 2009Applicant: FREESCALE SEMICONDUCTOR, INC.Inventors: Tahir A. Khan, Amitava Bose, Vishnu K. Khemka, Ronghua Zhu
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Patent number: 7550804Abstract: A semiconductor device may include a semiconductor substrate having a first dopant type. A first semiconductor region within the semiconductor substrate may have a plurality of first and second portions (44, 54). The first portions (44) may have a first thickness, and the second portions (54) may have a second thickness. The first semiconductor region may have a second dopant type. A plurality of second semiconductor regions (42) within the semiconductor substrate may each be positioned at least one of directly below and directly above a respective one of the first portions (44) of the first semiconductor region and laterally between a respective pair of the second portions (54) of the first semiconductor region. A third semiconductor region (56) within the semiconductor substrate may have the first dopant type. A gate electrode (64) may be over at least a portion of the first semiconductor region and at least a portion of the third semiconductor region (56).Type: GrantFiled: March 27, 2006Date of Patent: June 23, 2009Assignee: Freescale Semiconductor, Inc.Inventors: Vishnu K. Khemka, Amitava Bose, Todd C. Roggenbauer, Ronghua Zhu