Patents by Inventor Asanga H. Perera

Asanga H. Perera 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).

  • Patent number: 8969940
    Abstract: A process integration is disclosed for fabricating non-volatile memory (NVM) cells having patterned select gates (211, 213), charge storage layers (219), inlaid control gates (223, 224), and inlaid control gate contact regions (228).
    Type: Grant
    Filed: October 8, 2013
    Date of Patent: March 3, 2015
    Assignee: Freescale Semiconductor, Inc.
    Inventors: Jane A Yater, Cheong Min Hong, Sung-Taeg Kang, Asanga H Perera
  • Publication number: 20150054050
    Abstract: A method of making a semiconductor structure includes forming a select gate and a charge storage layer in an NVM region. A control gate is formed by depositing a conformal layer followed by an etch back. A patterned etch results in leaving a portion of the charge storage layer over the select gate and under the control gate and to remove the charge storage layer from the logic region. A logic gate structure formed in a logic region has a metal work function surrounded by an insulating layer.
    Type: Application
    Filed: August 21, 2013
    Publication date: February 26, 2015
    Inventors: ASANGA H. PERERA, Cheong Min Hong, Sung-Taeg Kang, Janes A. Yater
  • Publication number: 20150054049
    Abstract: A method of making a semiconductor structure includes forming a select gate and a charge storage layer in an NVM region. A spacer select gate is formed by depositing a conformal layer followed by an etch back. A patterned etch results in leaving a portion of the charge storage layer over the select gate. A dummy gate structure formed in a logic region has a dummy gate surrounded by an insulating layer. Performing chemical polishing results in the top surface of the charge storage layer being coplanar with top surface of the dummy gate structure. Replacing a portion of the dummy gate structure with a metal logic gate which includes a further chemical mechanical polishing results in the top surface of the charge storage layer being coplanar with the metal logic gate.
    Type: Application
    Filed: August 21, 2013
    Publication date: February 26, 2015
    Inventors: Asanga H. PERERA, Cheong Min HONG, Sung-Taeg KANG, Byoung W. MIN, Jane A. YATER
  • Publication number: 20150054044
    Abstract: A process integration is disclosed for fabricating non-volatile memory (NVM) cells (105-109, 113-115) on a first flash cell substrate area (111) which are encapsulated in one or more planar dielectric layers (116) prior to forming an elevated substrate (117) on a second CMOS transistor area (112) on which high-k metal gate electrodes (119-120, 122-126, 132, 134) are formed using a gate-last HKMG CMOS process flow without interfering with the operation or reliability of the NVM cells.
    Type: Application
    Filed: August 22, 2013
    Publication date: February 26, 2015
    Applicant: Freescale Semiconductor, Inc
    Inventors: Asanga H. Perera, Sung-Taeg Kang, Jane A. Yater, Cheong Min Hong
  • Publication number: 20150041875
    Abstract: A process integration is disclosed for fabricating non-volatile memory (NVM) cells having recessed control gates (118, 128) on a first substrate area (111) which are encapsulated in one or more planar dielectric layers (130) prior to forming in-laid high-k metal select gates and CMOS transistor gates (136, 138) in first and second substrate areas (111, 113) using a gate-last HKMG CMOS process flow without interfering with the operation or reliability of the NVM cells.
    Type: Application
    Filed: August 8, 2013
    Publication date: February 12, 2015
    Applicant: Freescale Seminconductor, Inc
    Inventor: Asanga H. Perera
  • Patent number: 8901632
    Abstract: A method of making a semiconductor structure includes forming a select gate over a substrate in an NVM region and a first protection layer over a logic region. A control gate and a storage layer are formed over the substrate in the NVM region. The control gate has a top surface below a top surface of the select gate. The charge storage layer is under the control gate, along adjacent sidewalls of the select gate and control gate, and is partially over the top surface of the select gate. A second protection layer is formed over the NVM portion and the logic portion. The first and second protection layers are removed from the logic region. A portion of the second protection layer is left over the control gate and the select gate. A gate structure, formed over the logic region, has a high k dielectric and a metal gate.
    Type: Grant
    Filed: September 30, 2013
    Date of Patent: December 2, 2014
    Assignee: Freescale Semiconductor, Inc.
    Inventors: Asanga H. Perera, Cheong Min Hong, Sung-Taeg Kang, Byoung W. Min, Jane A. Yater
  • Patent number: 8877585
    Abstract: A method of making a semiconductor structure using a substrate having a non-volatile memory (NVM) portion, a first high voltage portion, a second high voltage portion and a logic portion, includes forming a first conductive layer over an oxide layer on a major surface of the substrate in the NVM portion, the first and second high voltage portions, and logic portion. A memory cell is fabricated in the NVM portion while the first conductive layer remains in the first and second high voltage portions and the logic portion. The first conductive layer is patterned to form transistor gates in the first and second high voltage portions. A protective mask is formed over the NVM portion and the first and second high voltage portions. A transistor gate is formed in the logic portion while the protective mask remains in the NVM portion and the first and second high voltage portions.
    Type: Grant
    Filed: August 16, 2013
    Date of Patent: November 4, 2014
    Assignee: Freescale Semiconductor, Inc.
    Inventors: Asanga H. Perera, Cheong Min Hong, Sung-Taeg Kang
  • Patent number: 8871598
    Abstract: A method of making a semiconductor device includes forming a split gate memory gate structure on a memory region of a substrate, and protecting the split gate memory gate structure by depositing protective layers over the memory region including the memory gate structure and over a logic region of the substrate. The protective layers include a material that creates a barrier to diffusion of metal. The protective layers are retained over the memory region while forming a logic gate in the logic region. The logic gate includes a high-k dielectric layer and a metal layer. A spacer material is deposited over the logic gate. Spacers are formed on the memory gate structure and the logic gate. The spacer on the logic gate is formed of the spacer material and the spacer on the memory gate structure is formed with one of the protective layers.
    Type: Grant
    Filed: July 31, 2013
    Date of Patent: October 28, 2014
    Assignee: Freescale Semiconductor, Inc.
    Inventor: Asanga H. Perera
  • Patent number: 6524931
    Abstract: The reliability of integrated circuits fabricated with trench isolation is improved by forming a trench isolation structure with a void-free trench plug (36). In one embodiment, a polysilicon layer (28) is formed within a trench (22) and then subsequently oxidized to form a first dielectric layer (30). The first dielectric layer (30) is then etched and a second dielectric layer (34) is subsequently formed over the etched dielectric layer (32). A portion of the second dielectric layer (34) is then removed using chemical-mechanical polishing to form a void-free trench plug (36) within the trench (22). In addition, reliability is also improved by minimizing subsequent etching of trench plug (36) after it has been formed.
    Type: Grant
    Filed: July 20, 1999
    Date of Patent: February 25, 2003
    Assignee: Motorola, Inc.
    Inventor: Asanga H. Perera
  • Patent number: 6362057
    Abstract: A conductive layer (14) and a dummy feature (16) are formed over a semiconductor substrate (10) doped with a first dopant type. A spacer (42) is then formed adjacent the dummy feature (16) and is used to define a first patterned feature (92). In one embodiment, substrate regions (90) are doped with a second dopant type that is a same dopant type as the first dopant type. In an alternative embodiment, substrate regions (90) are doped with a second dopant type that is opposite the first dopant type. The dummy feature (16) is then removed and remaining portions of the spacer (100) are used to define a gate electrode (120). The substrate (10) is then doped optionally with a third dopant type and then with a fourth dopant type, the third and fourth dopant types being opposite the first dopant type, to form asymmetrically doped source (172) and drain regions (174) in the semiconductor substrate (10).
    Type: Grant
    Filed: October 26, 1999
    Date of Patent: March 26, 2002
    Assignee: Motorola, Inc.
    Inventors: William J. Taylor, Jr., Suresh Venkatesan, Asanga H. Perera
  • Patent number: 5786263
    Abstract: The reliability of integrated circuits fabricated with trench isolation is improved by forming a trench isolation structure with a void-free trench plug (36). In one embodiment, a polysilicon layer (28) is formed within a trench (22) and then subsequently oxidized to form a first dielectric layer (30). The first dielectric layer (30) is then etched and a second dielectric layer (34) is subsequently formed over the etched dielectric layer (32). A portion of the second dielectric layer (34) is then removed using chemical-mechanical polishing to form a void-free trench plug (36) within the trench (22). In addition, reliability is also improved by minimizing subsequent etching of trench plug (36) after it has been formed.
    Type: Grant
    Filed: April 4, 1995
    Date of Patent: July 28, 1998
    Assignee: Motorola, Inc.
    Inventor: Asanga H. Perera
  • Patent number: 5698893
    Abstract: A static-random-access memory (SRAM) cell has been devised which contains an access transistor having a first channel region with a first surface that lies along a first crystal plane; and a trench driver transistor having a second channel region with a second surface that lies along a second crystal plane. The first and second crystal planes belong to a single family of equivalent crystal planes, for example, the {100} family of planes. Orienting the surfaces of the channel regions of the two transistors in this fashion improves the beta ratio of the driver and access transistors and thus greatly improves the cell stability. The .beta. ratio is the ratio of the transconductances of the driver and access MOSFETs, or ##EQU1## and preferably has a value of at least three. Using a trench driver transistor improves the bit cell capacitance.
    Type: Grant
    Filed: January 3, 1995
    Date of Patent: December 16, 1997
    Assignee: Motorola, Inc.
    Inventors: Asanga H. Perera, J. David Burnett
  • Patent number: 5665202
    Abstract: A process for polish planarizing a fill material (40) overlying a semiconductor substrate (30) includes a multi-step polishing process. In one embodiment, a second planarization layer (42) is deposited over a fill material (40) and a portion of the fill material (40) is removed leaving a remaining portion (44). The pad pressure of a CMP apparatus (20) is adjusted such that a first pressure is generated during the polishing process. Then, the remaining portion (44) is removed, while operating the CMP apparatus (20) at a second pad pressure. The selectivity of the polishing process is maintained by reducing the pad pressure during the second polishing step. In a second embodiment, after the first polishing step is performed, the remaining portion (44) is removed by an etching process using a portion (46) of second planarization layer (42).
    Type: Grant
    Filed: November 24, 1995
    Date of Patent: September 9, 1997
    Assignee: Motorola, Inc.
    Inventors: Chitra K. Subramanian, Asanga H. Perera, James D. Hayden, Subramoney V. Iyer