Patents by Inventor Amitava Bose
Amitava Bose 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: 9790082Abstract: A device comprises a silicon-on-insulator (SOI) substrate having first and second silicon layers with an insulator layer interposed between them. A structural layer, having a first conductivity type, is formed on the first silicon layer. A well region, having a second conductivity type opposite from the first conductivity type, is formed in the structural layer, and resistors are diffused in the well region. A metallization structure is formed over the well region and the resistors. A first cavity extends through the metallization structure overlying the well region and a second cavity extends through the second silicon layer, with the second cavity stopping at one of the first silicon layer and the insulator layer. The well region interposed between the first and second cavities defines a diaphragm of a pressure sensor. An integrated circuit and the pressure sensor can be fabricated concurrently on the SOI substrate using a CMOS fabrication process.Type: GrantFiled: September 21, 2016Date of Patent: October 17, 2017Assignee: NXP USA, Inc.Inventors: Lianjun Liu, Amitava Bose
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Patent number: 9397233Abstract: A semiconductor process and apparatus provide a high voltage deep trench capacitor structure (10) that is integrated in an integrated circuit, alone or in alignment with a fringe capacitor (5). The deep trench capacitor structure is constructed from a first capacitor plate (4) that is formed from a doped n-type SOI semiconductor layer (e.g., 4a-c). The second capacitor plate (3) is formed from a doped p-type polysilicon layer (3a) that is tied to the underlying substrate (1).Type: GrantFiled: June 2, 2010Date of Patent: July 19, 2016Assignee: North Star Innovations Inc.Inventors: Ronghua Zhu, Vishnu Khemka, Amitava Bose, Todd C. Roggenbauer
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Patent number: 8188543Abstract: An electronic device can include a substrate, a buried insulating layer overlying the substrate, and a semiconductor layer overlying the buried insulating layer, wherein the semiconductor layer is substantially monocrystalline. The electronic device can also include a conductive structure extending through the semiconductor layer and buried insulating layer and abutting the substrate, and an insulating spacer lying between the conductive structure and each of the semiconductor layer and the buried insulating layer.Type: GrantFiled: November 3, 2006Date of Patent: May 29, 2012Assignee: Freescale Semiconductor, Inc.Inventors: Todd C. Roggenbauer, Vishnu K. Khemka, Ronghua Zhu, Amitava Bose, Paul Hui, Xiaoqiu Huang
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Patent number: 8134222Abstract: 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: GrantFiled: October 12, 2010Date of Patent: March 13, 2012Assignee: Freescale Semiconductor, Inc.Inventors: Tahir A. Khan, Amitava Bose, Vishnu K. Khemka, Ronghua Zhu
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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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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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Publication number: 20100230736Abstract: A semiconductor process and apparatus provide a high voltage deep trench capacitor structure (10) that is integrated in an integrated circuit, alone or in alignment with a fringe capacitor (5). The deep trench capacitor structure is constructed from a first capacitor plate (4) that is formed from a doped n-type SOI semiconductor layer (e.g., 4a-c). The second capacitor plate (3) is formed from a doped p-type polysilicon layer (3a) that is tied to the underlying substrate (1).Type: ApplicationFiled: June 2, 2010Publication date: September 16, 2010Inventors: Ronghua Zhu, Vishnu Khemka, Amitava Bose, Todd C. Roggenbauer
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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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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: 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: 7732274Abstract: A semiconductor process and apparatus provide a high voltage deep trench capacitor structure (10) that is integrated in an integrated circuit, alone or in alignment with a fringe capacitor (5). The deep trench capacitor structure is constructed from a first capacitor plate (4) that is formed from a doped n-type SOI semiconductor layer (e.g., 4a-c). The second capacitor plate (3) is formed from a doped p-type polysilicon layer (3a) that is tied to the underlying substrate (1).Type: GrantFiled: May 23, 2007Date of Patent: June 8, 2010Assignee: Freescale Semiconductor, Inc.Inventors: Ronghua Zhu, Vishnu Khemka, Amitava Bose, Todd C. Roggenbauer
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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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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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Patent number: 7608908Abstract: Higher voltage device isolation structures (40, 60, 70, 80, 90, 90?) are provided for semiconductor integrated circuits having strongly doped buried layers (24, 24?). One or more dielectric lined deep isolation trenches (27, 27?, 27?, 27??) separates adjacent device regions (411, 412; 611, 612; 711, 712; 811, 812; 911, 912). Electrical breakdown (BVdss) between the device regions (411, 412; 611, 612; 711, 712; 811, 812; 911, 912) and the oppositely doped substrate (22, 22?) is found to occur preferentially where the buried layer (24, 24?) intersects the dielectric sidewalls (273, 274; 273?, 274?; 273?, 274?) of the trench (27, 27?, 27?, 27??). The breakdown voltage (BVdss) is increased by providing a more lightly doped region (42, 42?, 62, 72, 82) of the same conductivity type as the buried layer (24, 24?), underlying the buried layer (24, 24?) at the trench sidewalls (273, 274; 273?, 274?; 273?, 274?).Type: GrantFiled: May 22, 2008Date of Patent: October 27, 2009Assignee: Freescale Semiconductor, Inc.Inventors: Vishnu Khemka, Amitava Bose, Michael C. Butner, Bernhard H. Grote, Tahir A. Khan, Shifeng Shen, Ronghua Zhu
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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
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Patent number: 7511319Abstract: A power metal-oxide-semiconductor field effect transistor (MOSFET)(100) incorporates a stepped drift region including a shallow trench insulator (STI)(112) partially overlapped by the gate (114) and which extends a portion of the distance to a drain region (122). A silicide block extends from and partially overlaps STI (112) and drain region (122). The STI (112) has a width that is approximately 50% to 75% of the drift region.Type: GrantFiled: February 24, 2006Date of Patent: March 31, 2009Assignee: Freescale Semiconductor, Inc.Inventors: Ronghua Zhu, Amitava Bose, Vishnu K. Khemka, Todd C. Roggenbauer