Plural Wells Patents (Class 438/228)
  • Patent number: 6900081
    Abstract: A semiconductor device has a depletion type MIS transistor, a transistor forming a masked ROM, and a submicron CMOS integrated on a single or common semiconductor substrate, while minimizing the steps of manufacturing the depletion type MIS transistor. During implantation of ions for changing an enhancement type transistor into a depletion type transistor, impurity ions can be implanted to change the transistor forming the masked ROM into resistance, so that the depletion type transistor, the transistor constituting the mark ROM, and a submicron CMOS can be integrated on a single or common semiconductor substrate.
    Type: Grant
    Filed: August 19, 2003
    Date of Patent: May 31, 2005
    Assignee: Fuji Electronic Co., Ltd.
    Inventor: Akio Kitamura
  • Patent number: 6900091
    Abstract: An structure for electrically isolating a semiconductor device is formed by implanting dopant into a semiconductor substrate that does not include an epitaxial layer. Following the implant the structure is exposed to a very limited thermal budget so that dopant does not diffuse significantly. As a result, the dimensions of the isolation structure are limited and defined, thereby allowing a higher packing density than obtainable using conventional processes which include the growth of an epitaxial layer and diffusion of the dopants. In one group of embodiments, the isolation structure includes a deep layer and a sidewall which together form a cup-shaped structure surrounding an enclosed region in which the isolated semiconductor device may be formed. The sidewalls may be formed by a series of pulsed implants at different energies, thereby creating a stack of overlapping implanted regions.
    Type: Grant
    Filed: August 14, 2002
    Date of Patent: May 31, 2005
    Assignee: Advanced Analogic Technologies, Inc.
    Inventors: Richard K. Williams, Michael E. Cornell, Wai Tien Chan
  • Patent number: 6881634
    Abstract: In one embodiment, a buried-channel transistor is fabricated by masking a portion of an active region adjacent to a trench and implanting a dopant in an exposed portion of the active region to adjust a threshold voltage of the transistor. By masking a portion of the active region, the dopant is substantially prevented from getting in a region near an edge of the trench. Among other advantages, this results in reduced leakage current.
    Type: Grant
    Filed: August 30, 2002
    Date of Patent: April 19, 2005
    Assignee: Cypress Semiconductor Corporation
    Inventor: Jeffrey T. Watt
  • Patent number: 6875663
    Abstract: The present invention provides a method of fabricating a semiconductor device in which deterioration in a transistor characteristic is prevented by preventing a channel stop implantation layer from being formed in an active region. A resist mask is formed so as to have an opening over a region in which a PMOS transistor is formed. Channel stop implantation is performed with energy by which ions pass through a partial isolation oxide film and a peak of an impurity profile is generated in an SOI layer, thereby forming a channel stop layer in the SOI layer under the partial isolation oxide film, that is, an isolation region. An impurity to be implanted here is an N-type impurity. In the case of using phosphorus, its implantation energy is set to, for example, 60 to 120 keV, and the density of the channel stop layer is set to 1×1017 to 1×1019/cm3. At this time, the impurity of channel stop implantation is not stopped in the SOI layer corresponding to the active region.
    Type: Grant
    Filed: September 9, 2002
    Date of Patent: April 5, 2005
    Assignee: Renesas Technology Corp.
    Inventors: Toshiaki Iwamatsu, Takashi Ipposhi, Takuji Matsumoto, Shigenobu Maeda
  • Patent number: 6875650
    Abstract: On the surface of a semiconductor material of a first conductivity type 101a, a lateral MOS transistor 100 is described surrounded by a well 171 of the opposite conductivity type and, nested within the well, an electrical isolation region 102. The semiconductor region 101a embedding this transistor has a resistivity higher than the remainder of the semiconductor material 101 and further contains a buried layer 160 of the opposite conductivity type. This layer 160 extends laterally to the wells 171, thereby electrically isolating the near-surface portion of the semiconductor region from the remainder of the semiconductor material, and enabling the MOS transistor to operate as an electrically isolated high-voltage I/O transistor for circuit noise reduction, while having low drain junction capacitance. In the first embodiment of the invention (FIG.
    Type: Grant
    Filed: October 14, 2003
    Date of Patent: April 5, 2005
    Assignee: Texas Instruments Incorporated
    Inventors: Craig T. Salling, Zhiqiang Wu
  • Patent number: 6853037
    Abstract: A semiconductor device includes a relatively lower threshold level MOSFET and relatively higher threshold level MOSFETs of n- and p-types. The higher threshold level MOSFETs have gate oxide films which is thicker than that of the lower threshold level MOSFET and, in addition, the gate oxide film of the higher threshold level MOSFET of n-type is thicker than that of the higher threshold level MOSFET of p-type. To fabricate the semiconductor device, implantation treatments of fluorine ions are carried out before the gate oxide treatment. Specifically, as for the higher threshold level MOSFETs of n- and p-types, implantation treatments of fluorine ions are independently carried out with unique implantation conditions.
    Type: Grant
    Filed: June 4, 2001
    Date of Patent: February 8, 2005
    Assignee: NEC Electronics Corporation
    Inventors: Tomohiko Kudo, Naohiko Kimizuka
  • Patent number: 6841430
    Abstract: A semiconductor device with p-channel and n-channel field effect devices formed on a common substrate, where the drain and source regions of the n-channel field effect device are formed within a silicon epitaxial layer formed on a silicon layer germanium relax which is formed on a silicon germanium buffer layer with a graduated germanium concentration. Additionally, drain and source regions of the p-channel field effect device are formed within a silicon-germanium compound layer formed on the substrate and the silicon epitaxial cap layer formed on the silicon-germanium compound layer.
    Type: Grant
    Filed: April 6, 2004
    Date of Patent: January 11, 2005
    Assignee: Sony Corporation
    Inventors: Minoru Sugawara, Takashi Noguchi
  • Patent number: 6838328
    Abstract: A plurality of p-wells and n-wells are formed in a front side of a bulk material, and a plurality of n layers and p layers are alternately formed within the bulk material between a back side of the bulk material and the plurality of n-wells and p-wells. The plurality of n layers are electrically isolated from one another and respectively route different potentials to selected ones of the plurality of n-wells, and likewise, the plurality of p layers are electrically isolated from one another and respectively route different potentials to selected ones of the plurality of p-wells.
    Type: Grant
    Filed: October 10, 2003
    Date of Patent: January 4, 2005
    Assignee: Sun Microsystems, Inc.
    Inventor: James B. Burr
  • Patent number: 6806160
    Abstract: A method for forming a lateral SCR device for on-chip ESD protection in shallow-trench-isolation CMOS process is provided. In the present lateral SCR device, the shallow trench isolation among the current conduction path of the lateral SCR device is removed and instead of a dummy gate. Thereby, the SCR device has a narrower anode-to-cathode spacing, and then the lateral SCR device can be turned on more quickly to protect the CMOS IC's in ESD events. Additionally, the silicon area of the substrate occupied by the lateral SCR device is also saved. This method for forming a lateral SCR device without shallow-trench-isolation regions in its current path can be fully process-compatible to general CMOS technologies by only changing layout patterns in the mask layers.
    Type: Grant
    Filed: June 25, 2002
    Date of Patent: October 19, 2004
    Assignee: United Microelectronics Corp.
    Inventors: Ming-Dou Ker, Chyh-Yih Chang, Tien-Hao Tang
  • Patent number: 6806133
    Abstract: A method for fabricating a triple well in a semiconductor device, includes the steps of forming a first well of a first conductive type with a first concentration lower than a first target concentration, wherein the first concentration is the minimum dose capable of isolating neighboring wells each other and forming a second well of a second conductive type with a second concentration higher than a second target concentration, wherein the second well includes a first region surrounded by the first well and a second region isolated from the first region by the first well.
    Type: Grant
    Filed: December 30, 2002
    Date of Patent: October 19, 2004
    Assignee: Hynix Semiconductor Inc.
    Inventor: Jae-Geun Oh
  • Patent number: 6787410
    Abstract: A semiconductor device with dynamic threshold transistors includes a complex element isolation region composed of a shallow element isolation region made of shallow trench isolation and deep element isolation regions provided on both sides of the shallow element isolation region. Since the shallow element isolation region is made of the shallow trench isolation, Bird's beak in the shallow element isolation region is small. This prevents off leakage failure due to stress caused by the bird's beak. The deep element isolation region has an approximately constant width which allows the complex element isolation region to be wide.
    Type: Grant
    Filed: December 19, 2002
    Date of Patent: September 7, 2004
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Hiroshi Iwata, Akihide Shibata, Seizo Kakimoto
  • Patent number: 6773976
    Abstract: A semiconductor device and method of manufacturing the semiconductor device including a semiconductor substrate of a first conductivity type. A scribe lane area formed in the substrate to define chip formation areas. A deep well area formed in each chip formation area. The deep well area has a second conductivity type which is opposite the first conductivity type. Also, at least one well area is formed within the deep well area.
    Type: Grant
    Filed: March 29, 2001
    Date of Patent: August 10, 2004
    Assignee: Hyundai Eletronics Industries Co., Ltd.
    Inventor: Ha Zoong Kim
  • Patent number: 6762086
    Abstract: A method for fabricating a semiconductor device, includes the steps of forming a triple well including a first conductive type well in a semiconductor substrate, wherein a cell transistor is to be formed on the first conductive type well, sequentially forming a gate oxide layer and a gate electrode on a triple well, forming a source/drain region in the first conductive type well by implanting second conductive type dopant and forming a threshold voltage ion implantation region beneath the gate electrode by implanting first conductive type dopant to the first conductive type well with a ion implantation energy enough to pass through the gate electrode, wherein the threshold voltage ion implantation region surrounds the source/drain region.
    Type: Grant
    Filed: December 31, 2002
    Date of Patent: July 13, 2004
    Assignee: Hynix Semiconductor Inc.
    Inventor: Jae-Geun Oh
  • Patent number: 6707115
    Abstract: A device comprising: a layer of gate oxide on a surface of the semiconductor substrate; a gate electrode formed on the surface of the gate oxide, the gate electrode having a drain side; a p-well implanted within a semiconductor substrate under the gate electrode; an n-well implanted in the p-well on the drain side; an n+ source region in the p-well outside of the n-well; an n+ drain region within the substrate inside the n-well; and lightly doped regions extending respectively from the source and drain regions toward the gate electrode.
    Type: Grant
    Filed: April 16, 2001
    Date of Patent: March 16, 2004
    Assignee: AirIP Corporation
    Inventor: Dominik J. Schmidt
  • Patent number: 6699740
    Abstract: A semiconductor device including a P-type semiconductor layer; an N-type first well on the surface of the semiconductor layer; a P-type second well on the surface of the first well; an N-type source region on the surface of the second well; and an N-type drain region on the surface of the first well and apart from the source region at a specific distance. A gate electrode is formed on the semiconductor layer and extends from the source region to the second well and the first well. An application electrode is arranged apart from the gate electrode on the first well between the second well and the drain region, and extends from the first well to the edge thereof. A P-type first impurity diffusion layer is formed on the surface of the source region and extends to the second well under the source region.
    Type: Grant
    Filed: February 15, 2002
    Date of Patent: March 2, 2004
    Assignee: Oki Electric Industry Co., Ltd.
    Inventor: Isao Kimura
  • Patent number: 6677210
    Abstract: High voltage transistors with high breakdown voltages are provided. These high voltage transistors are formed with graded drain extension regions. The concentration of charge carriers increases farther away from the gate across each drain extension region, causing severe electric fields to be moved away from the gate. Methods and structures of the present invention may be used to increase a transistor's breakdown voltage to the theoretical limit of the device. High voltage transistors with graded extension regions may be p-channel or n-channel MOSFETs.
    Type: Grant
    Filed: February 28, 2002
    Date of Patent: January 13, 2004
    Assignee: Linear Technology Corporation
    Inventor: Francois Hebert
  • Publication number: 20040002185
    Abstract: This invention relates to a CMOSFET 10 in which a p-type gate electrode 32a and an n-type gate electrode 32b are formed on a silicon substrate 12. The p-type gate electrode 32a comprises, in order, a p-type polycrystalline silicon layer 22a and a tungsten silicide layer 26a. The n-type gate electrode 32b comprises, in order, an n-type polycrystalline silicon layer 22b and a tungsten silicide layer 26b. A carbon-containing polycrystalline silicon layer 24, which is an impurity thermal diffusion prevention layer to suppress the interdiffusion of impurities, is provided between the p-type polycrystalline silicon layer 22a and the tungsten silicide layer 26a.
    Type: Application
    Filed: October 24, 2002
    Publication date: January 1, 2004
    Inventor: Masashi Takahashi
  • Patent number: 6667205
    Abstract: A method of forming retrograde n-wells and p-wells. A first mask is formed on the substrate and the n-well implants are carried out. Then the mask is thinned, and a deep p implant is carried out with the thinned n-well mask in place. This prevents Vt shifts in FETs formed in the n-well adjacent the nwell-pwell interface. The thinned mask is then removed, a p-well mask is put in place, and the remainder of the p-well implants are carried out.
    Type: Grant
    Filed: April 19, 2002
    Date of Patent: December 23, 2003
    Assignee: International Business Machines Machines Corporation
    Inventors: Matthew J. Breitwisch, Chung H. Lam, James A. Slinkman
  • Patent number: 6664602
    Abstract: An object of the invention is to suppress degradation of the effective isolation width between a well and a diffusion layer caused by impurity ion implantation for forming the well performed at a predetermined incident angle. A well is formed by performing impurity ion implantation twice: first impurity ion implantation from a first direction at predetermined incident angle, acceleration voltage and dose; and second impurity ion implantation from a second direction different from the first direction by 180 degrees in a plan view at the same incident angle, acceleration voltage and dose as those in the first impurity ion implantation.
    Type: Grant
    Filed: July 15, 2002
    Date of Patent: December 16, 2003
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Tomohiro Yamashita, Masashi Kitazawa
  • Publication number: 20030228731
    Abstract: A method is provided for manufacturing a semiconductor device that can reduce the number of steps in manufacturing a triple-well that includes multiple ion implantation steps and heat treatment steps.
    Type: Application
    Filed: March 5, 2003
    Publication date: December 11, 2003
    Inventor: Masahiro Hayashi
  • Patent number: 6645854
    Abstract: A substantially vertical isolation junction between semiconductor devices is provided. The substantially vertical junction between a P-doped region and an N-doped region allows the P-doped region to be adjacent to the N-doped region with a lateral stagger with a width that is less than 0.1 of the depth. The substantially vertical junction is created by placing a first mask over part of a substrate. A first series of implants of a first dopant is implanted in the substrate. The first mask is removed and a second mask is placed over part of the substrate. A second series of implants of a second dopant of a second conductivity is then implanted in the substrate. A substantially vertical junction results.
    Type: Grant
    Filed: December 19, 2001
    Date of Patent: November 11, 2003
    Assignee: National Semiconductor Corporation
    Inventor: Peter J. Hopper
  • Publication number: 20030186503
    Abstract: A modified STI process is provided comprising forming a first polysilicon layer over a substrate. Forming a trench through the first polysilicon layer and into the substrate, and filling the trench with an oxide layer. Depositing a second polysilicon layer over the oxide, such that the bottom of the second polysilicon layer within the trench is above the bottom of the first polysilicon layer, and the top of the second polysilicon layer within the trench is below the top of the first polysilicon layer. The resulting structure may then be planarized using a CMP process. An alignment key may be formed by selectively etching the oxide layer. A third polysilicon layer may then be deposited and patterned using photoresist to form a gate structure. During patterning, exposed second polysilicon layer is etched. An etch stop is detected at the completion of removal of the second polysilicon layer. A thin layer of the first polysilicon layer remains, to be carefully removed using a subsequent selective etch process.
    Type: Application
    Filed: March 29, 2002
    Publication date: October 2, 2003
    Inventors: David R. Evans, Sheng Teng Hsu, Bruce D. Ulrich, Douglas J. Tweet, Lisa H. Stecker
  • Patent number: 6610581
    Abstract: There is disclosed a method of forming an isolation film in a semiconductor device, the method including the steps of: forming a silicon oxide film and a silicon nitride film in that order on a silicon substrate, using a resist pattern as a mask, etching the silicon nitride film and silicon oxide film, and forming trenches in the substrate. In the substrate, the respective trenches form a region in which isolation films are to be formed, and the region between the trenches forms an active region. In this case, each dimension is set so that a ratio W/t of width W to thickness t of the patterned silicon nitride film is 3.8 or more. Subsequently, by removing the resist pattern, subsequently using the silicon nitride film as the mask, and performing thermal oxidation at a temperature of 1050° C. to 1150° C. in an oxygen atmosphere, an isolation film is formed in the trench.
    Type: Grant
    Filed: June 1, 2000
    Date of Patent: August 26, 2003
    Assignee: Sanyo Electric Co., Ltd.
    Inventors: Yasuhiro Takeda, Hideaki Fujiwara
  • Patent number: 6589834
    Abstract: The dynamic random access memory (DRAM) cells in a semiconductor chip are isolated from the peripheral circuitry by forming the DRAM cells directly in the substrate while the peripheral and other functional circuits are formed in wells that are isolated from the substrate. In addition to providing isolation, the placement of the DRAM cells also reduces the leakage current in the cells, thereby increasing the time that a DRAM cell can hold a charge without being refreshed.
    Type: Grant
    Filed: May 3, 2001
    Date of Patent: July 8, 2003
    Assignee: Alliance Semiconductor Corporation
    Inventors: Chitranjan N. Reddy, Ritu Shrivastava
  • Patent number: 6583044
    Abstract: A buried channel and a method of fabricating a buried channel in a substrate including depositing a layer of masking material onto a surface of a substrate, etching a groove in the masking layer, etching a channel into the substrate through the groove, and depositing a cover layer over the masking layer and groove such that the covering layer at least substantially closes over the groove.
    Type: Grant
    Filed: June 26, 2001
    Date of Patent: June 24, 2003
    Assignee: Agilent Technologies, Inc.
    Inventors: Sandeep Bahl, Karen L. Seaward
  • Patent number: 6569713
    Abstract: A method of fabricating a read only memory. After forming bit lines and word lines in a substrate, a coding process is performed. A photoresist layer is formed on the substrate while performing the coding process. The photoresist layer covering a part of a first channel region under the word line is exposed, and then the photoresist layer covering a part of a second channel region under the word lines is exposed. A development step is performed to remove the photoresist layer that has been exposed. Using the remaining photoresist layer as a mask to perform an ion implantation, a coding area is formed in the first channel region and the second channel region. The photoresist layer is removed.
    Type: Grant
    Filed: June 15, 2001
    Date of Patent: May 27, 2003
    Assignee: Macronix International Co., Ltd.
    Inventor: Chih-Ping Chen
  • Publication number: 20030082895
    Abstract: A method for reducing a gate length bias is disclosed. The method utilizes an additional blanket ion implantation process to adjust the etching property of the undoped conductive layer such as a polysilicon layer used to form NMOS and PMOS gate electrodes so that the gate length bias between the NMOS gate electrodes and the PMOS gate electrodes can be effectively reduced.
    Type: Application
    Filed: April 8, 2002
    Publication date: May 1, 2003
    Inventors: Kai-Jen Ko, Yuan-Li Tsai, Ming-Hui Wu, Steven Huang, Ching-Chun Huang
  • Publication number: 20030077845
    Abstract: An integrated circuit is manufactured by providing a P− or P−− type semiconductor substrate with a resistivity of 10 to 1000 &OHgr;·cm, disposing a CMOS on top of the semiconductor substrate, depositing an insulating film with several wirings embedded therein over the CMOS, and disposing an inductor on top of the insulating film in a region that is apart from where the CMOS is positioned. A p+ type diffused layer with a resistivity of about 0.01 &OHgr;·cm is disposed between the semiconductor substrate and the CMOS.
    Type: Application
    Filed: October 17, 2002
    Publication date: April 24, 2003
    Inventors: Hiroaki Ohkubo, Yasutaka Nakashiba
  • Publication number: 20030064560
    Abstract: This invention provides a semiconductor device having stable characteristics of break down voltage and on resistance and the like. More specifically, this invention provides a semiconductor device comprising: a P-type semiconductor layer; an N-type first well formed on the surface of the semiconductor layer; a P-type second well formed on the surface of the first well; an N-type source region formed on the surface of the second well; an N-type drain region formed on the surface of the first well and formed apart from the source region at a specific distance; a gate electrode formed on the semiconductor layer and extending from the source region to the second well and the first well; an application electrode arranged apart from the gate electrode, arranged on the first well between the second well and the drain region and extending from the first well to the edge thereof; and a P-type first impurity diffusion layer formed on the surface of the second well and reaching the second well under the source region.
    Type: Application
    Filed: February 15, 2002
    Publication date: April 3, 2003
    Inventor: Isao Kimura
  • Patent number: 6531356
    Abstract: Embodiments include a semiconductor device including a well structure such that well areas can be formed with a higher density of integration and a plurality of high-voltage endurable transistors can be driven independently of one another with different voltages, and a method of manufacturing the semiconductor device. The semiconductor device may include a triple well comprising a first well formed in a silicon substrate and having a first conductivity type (P-type), a second well formed in adjacent relation to the first well and having a second conductivity type (N-type), and a third well formed in the second well and having the first conductivity type (P-type). A high-voltage endurable MOSFET is provided in each of the wells. Each MOSFET has an offset area in the corresponding well around a gate insulating layer. The offset area is formed of a low-density impurity layer which is provided under an offset LOCOS layer on the silicon substrate.
    Type: Grant
    Filed: January 27, 2000
    Date of Patent: March 11, 2003
    Assignee: Seiko Epson Corporation
    Inventor: Masahiro Hayashi
  • Patent number: 6521940
    Abstract: The invention relates to device processing, packaging and interconnects that will yield integrated electronic circuitry of higher density and complexity than can be obtained by using conventional multi-chip modules. Processes include the formation of complex multi-function circuitry on common module substrates using circuit tiles of silicon thin-films which are transferred, interconnected and packaged. Circuit modules using integrated transfer/interconnect processes compatible with extremely high density and complexity provide large-area active-matrix displays with on-board drivers and logic in a complete glass-based modules. Other applications are contemplated, such as, displays, microprocessor and memory devices, and communication circuits with optical input and output.
    Type: Grant
    Filed: August 30, 2000
    Date of Patent: February 18, 2003
    Assignee: Kopin Corporation
    Inventors: Duy-Phach Vu, Brenda Dingle, Ngwe Cheong
  • Patent number: 6521515
    Abstract: Metal silicides form low resistance contacts on semiconductor devices such as transistors. Rough interfaces are formed between metal silicide contacts, such as NiSi and the source/drain regions of a transistor, such as doped source/drain regions. Interfaces with a high degree of roughness result in increased spiking and junction leakage. Interface roughness is minimized by deeply doping the source/drain regions of a silicon on insulator substrate.
    Type: Grant
    Filed: September 15, 2000
    Date of Patent: February 18, 2003
    Assignee: Advanced Micro Devices, Inc.
    Inventor: George Jonathan Kluth
  • Patent number: 6518154
    Abstract: MOS transistors and CMOS devices comprising a plurality of transistors including metal-based gate electrodes of different composition are formed by a process comprising: depositing a first blanket layer of a first metal on a thin gate insulator layer extending over first and second active device (e.g.
    Type: Grant
    Filed: March 21, 2001
    Date of Patent: February 11, 2003
    Assignee: Advanced Micro Devices, Inc.
    Inventors: Matthew S. Buynoski, Qi Xiang, Paul R. Besser
  • Patent number: 6503787
    Abstract: The present invention provides a semiconductor device, formed on a semiconductor wafer, comprising a tub, first and second active areas, and an interconnect. In one aspect of the present invention, the tub is formed in the substrate of the semiconductor wafer and first and second active areas are in contact with the tub. In one advantageous embodiment, the interconnect is formed in the tub and is in electrical contact with the first and second active areas. The interconnect extends from the first active area to the second active area to electrically connect the first and second active areas.
    Type: Grant
    Filed: August 3, 2000
    Date of Patent: January 7, 2003
    Assignee: Agere Systems Inc.
    Inventor: Seungmoo Choi
  • Patent number: 6500705
    Abstract: A semiconductor memory device has a silicon substrate 10. A first embedded layer 11 is formed in the silicon substrate 10 under a p-well 18 in an area below a region where a drain 36 of a driver transistor 30 is located. The first embedded layer 11 makes a junction with the p-well 18. Also, the first embedded layer 11 is formed below an n-well 16 and contacts the n-well 16. When the drain 36 of the driver transistor 30 is at a voltage of 3V, &agr;-ray may pass through the p-well 18, the first embedded layer 11 and the silicon substrate 10. As a result, electron-hole pairs are cut. Due to the presence of the p-n junction that is formed by the p-well 18 and the first embedded layer 11, only electrons in the p-well 18 are drawn to the drain 36. As a result, a fall in the drain voltage of 3V is reduced. As a consequence, the device structure makes it difficult to destroy retained data.
    Type: Grant
    Filed: September 14, 2001
    Date of Patent: December 31, 2002
    Assignee: Seiko Epson Corporation
    Inventor: Takashi Kumagai
  • Patent number: 6489191
    Abstract: A method for forming a CMOS transistor gate with a self-aligned. channel implant. A semiconductor structure having a first active area is provided. A first insulating layer is formed on the semiconductor structure, and a second insulating layer is formed on the first insulating layer. The second insulating layer is patterned using a poly reverse mask and an etch selective to the first insulating layer to form a first channel implant opening, and the poly reverse mask is removed. A first channel implant mask is formed exposing the first channel implant opening. Impurity ions are implanted through the first channel implant opening to form a first threshhold adjust region and a first anti-punchthrough region. A gate layer is formed over the semiconductor structure, and the first gate layer is planarized to form a gate electrode. The second insulating layer is removed, and lightly doped source and drain regions, sidewall spacers and source and drain regions can be formed adjacent the gate electrode.
    Type: Grant
    Filed: May 8, 2002
    Date of Patent: December 3, 2002
    Assignee: Chartered Semiconductor Manufacturing Ltd.
    Inventors: Kai Shao, Yimin Wang, Jian Xun Li, Shao-Fu Sanford Chu
  • Patent number: 6486013
    Abstract: A semiconductor device has, in one embodiment, two wells of different conductivity types formed in a semiconductor substrate. The two wells are arranged to be adjacent to each other to form a junction therebetween. A field oxide film is formed to cover the junction at a main surface of the semiconductor substrate. Other field oxide films or field-shield isolation structures may be formed to isolate circuit elements from one another in the wells.
    Type: Grant
    Filed: January 8, 2001
    Date of Patent: November 26, 2002
    Assignee: Nippon Steel Corporation
    Inventors: Atsushi Kawasaki, Kohei Eguchi, Katsuki Hazama, Fumitaka Sugaya
  • Patent number: 6482692
    Abstract: A semiconductor device has, in one embodiment, two wells of different conductivity types formed in a semiconductor substrate. The two wells are arranged to be adjacent to each other to form a junction therebetween. A field oxide film is formed to cover the junction at a main surface of the semiconductor substrate. Other field oxide films or field-shield isolation structures may be formed to isolate circuit elements from one another in the wells.
    Type: Grant
    Filed: November 30, 2000
    Date of Patent: November 19, 2002
    Assignee: Nippon Steel Corporation
    Inventors: Atsushi Kawasaki, Kohei Eguchi, Katsuki Hazama, Fumitaka Sugaya
  • Patent number: 6468099
    Abstract: A method of fabricating a semiconductor device applies a LOCOS profile characteristic to an edge portion of an STI in a HV region to thereby lower compressive stress that is concentrated on the side of the STI. A field oxide film is formed so that only edge portions of HV region (active region II) may be in contact with a comparatively stiff STI, and then, a thick gate oxide film is formed on the HV region by utilizing a nitride film as a mask. After the nitride film as a mask is removed, a thin gate oxide film is formed on a LV region (an active region I in which a thin gate oxide film is formed). As a result, a thinning phenomenon of a gate oxide film at an edge portion of STI is prevented that otherwise would occur when the gate oxide film for HV grows in a normal STI structure by utilizing a nitride film as a mask.
    Type: Grant
    Filed: August 29, 2001
    Date of Patent: October 22, 2002
    Assignee: Samsung Electronics Co., Ltd.
    Inventor: Myoung-Soo Kim
  • Patent number: 6468850
    Abstract: A semiconductor device has a semiconductor substrate having a peripheral circuit area and a memory cell area. A border region having a well of a first conductivity is formed between the peripheral circuit area and the memory cell area. A well of a second conductivity is formed in the peripheral circuit area. The well in the peripheral circuit area is in contact with the border region but not in contact with the memory cell area. Dummy transistors are formed in the border region. The dummy transistors are arranged with substantially the same transistor forming density as that of the memory cell area.
    Type: Grant
    Filed: July 16, 2001
    Date of Patent: October 22, 2002
    Assignee: Seiko Epson Corporation
    Inventors: Junichi Karasawa, Kunio Watanabe, Takashi Kumagai
  • Patent number: 6461920
    Abstract: In a semiconductor device, a plurality of MIS transistors of the same conductivity type having different thresholds are formed at a main surface of semiconductor substrate, and impurity profiles on section extending in a depth direction from the main surface of the semiconductor substrate through respective channel regions of the plurality of MIS transistors have peaks located at different depths. This structure is formed by ion implantation performed on the respective channel regions with different implanting energies or different ion species. According to this semiconductor device, the thresholds of the MIS transistors can be individually controlled, and transistor characteristics optimum for uses can be obtained.
    Type: Grant
    Filed: September 5, 2000
    Date of Patent: October 8, 2002
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Masayoshi Shirahata, Yoshinori Okumura
  • Patent number: 6461908
    Abstract: A method of manufacturing a semiconductor device including a PMOS transistor (6) and an NMOS transistor (5) comprises the steps of: (a) providing a semiconductor substrate (1) having a P-well region (3), which is to be provided with the NMOS transistor (5), and an N-well region (2), which is to be provided with the PMOS transistor (6); (b) forming gate electrodes (8) on the P-well region (3) and the N-well region (2); (c) applying a hard mask (10), which covers either the P-well region (3) or the N-well region (2); (d) implanting a source and a drain in the region that is not covered by the hard mask (10), followed by heat activation; (e) implanting pocket implants in the region that is not covered by the hard mask (10), followed by heat activation; (f) removing the hard mask (10).
    Type: Grant
    Filed: April 10, 2001
    Date of Patent: October 8, 2002
    Assignee: Koninklijke Phillips Electronics N.V.
    Inventors: Peter Adriaan Stolk, Pierre Hermanus Woerlee, Mathijs Johan Knitel, Anja Catharina Maria Carolina Van Brandenburg
  • Patent number: 6461921
    Abstract: The work surface of a p-type silicon substrate has a section where an E type MOSFET is formed, and a section where an I type MOSFET having a threshold voltage of about 0.1V is formed. The MOSFET is formed using a p-type well layer having a resistivity lower than that of the ground of the silicon substrate. The well layer includes deep and shallow portions which are integrally formed and have the same resistivity. The deep well portion defines an element area for forming the MOSFET, whereas the shallow well portions are arranged immediately below element isolation films surrounding the I type MOSFET, and function as channel stoppers.
    Type: Grant
    Filed: July 11, 2000
    Date of Patent: October 8, 2002
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Norihisa Arai
  • Publication number: 20020137272
    Abstract: An efficient method for fabricating dual well type structures uses the same number of masks used in single well type structure fabrication. In a preferred embodiment, the current invention allows low voltage and high voltage n-channel transistors and low voltage and high voltage p-channel transistors to be formed in a single substrate. One mask is used for forming a diffusion well, a second mask for both forming a retrograde well and doping the well to achieve an intermediate threshold voltage in that well, and a third mask for both differentiating the gate oxides for the low voltage devices and doping the threshold voltages to achieve the final threshold voltages.
    Type: Application
    Filed: April 15, 2002
    Publication date: September 26, 2002
    Inventor: Mark A. Helm
  • Patent number: 6455363
    Abstract: A method for fabricating an SRAM device having a standard well tub, where an additional well tub is deposited within the standard well tub. In this manner, the dopant concentration is increased in the well area of the SRAM device, which increases both the isolation punchthrough tolerance and the SER immunity of the device. The additional well tub is deposited to a depth that is shallower than the standard well tub. The additional well tub is deposited using an ion implantation process using the same mask set as that used for the threshold voltage adjustment deposition. Thus, no additional mask layer is required to deposit the additional well tub, and the all of the expenses normally associated with an additional mask layer are avoided.
    Type: Grant
    Filed: July 3, 2000
    Date of Patent: September 24, 2002
    Assignee: LSI Logic Corporation
    Inventors: Helmut Puchner, Gary K. Giust, Weiran Kong
  • Patent number: 6455402
    Abstract: The method of fabricating a semiconductor device includes the steps of selectively forming an insulating oxide layer in a semiconductor substrate having a first conductivity type, wherein the semiconductor substrate has first and second regions; forming impurity layers having a second conductivity type in the first and second regions of the semiconductor substrate; forming a first mask layer in the second region of the semiconductor substrate; forming impurity layers having the second conductivity type in the first region of the semiconductor substrate by performing serial ion implantations with different doses of dopants at different acceleration energies; forming a second mask layer in the first region of the semiconductor substrate; and forming impurity layers having the first conductivity type in the second region of the semiconductor substrate by performing serial ion implantations with different doses of dopants at different acceleration energies.
    Type: Grant
    Filed: March 20, 2001
    Date of Patent: September 24, 2002
    Assignee: Hyundai Electronics Industries Co., Ltd.
    Inventors: Joo-Hyong Lee, Jeong-Hwan Son
  • Patent number: 6451640
    Abstract: There is provided a method of fabricating a semiconductor device, including the steps of (a) forming first well regions in a semiconductor substrate in all regions in which high-voltage and low-voltage MOS transistors are to be formed, the semiconductor At e having a first conductivity and the first well regions having a second conductivity, (b) forming an isolation layer on the semiconductor substrate for isolating the first well regions from each other, (c) forming high-voltage well regions having a first conductivity and low-voltage well regions one of which has a first conductivity and another of which has a second conductivity, and (d) forming MOS transistors on the high-voltage and low-voltage well regions. The high-voltage and low-voltage well regions are formed with the isolation layer being used as a mark. The above-mentioned method makes it possible to form low-voltage and high-voltage MOS transistors on a common semiconductor substrate in the smallest number of fabrication steps.
    Type: Grant
    Filed: July 5, 2000
    Date of Patent: September 17, 2002
    Assignee: NEC Corporation
    Inventor: Toshihiko Ichikawa
  • Publication number: 20020123189
    Abstract: There is disclosed a method of manufacturing a transistor in a semiconductor device. The present invention forms a Ta film or a TaNx film at a low temperature or forms a first TaNx film in which the composition(x) of nitrogen is 0.45˜0.55, on a gate insulating film in a NMOS region, so that the work function becomes 4.0˜4.4 eV, and also forms a Ta film or a TaNx film at a high temperature or forms a second TaNx film in which the composition(x) of nitrogen is 0.6˜1.4 is formed, on a gate insulating film in a PMOS region, so that the work function becomes 4.8˜5.2 eV. Thus, the present invention can lower the threshold voltage by implementing a surface channel CMOS device both in the NMOS region and the PMOS region.
    Type: Application
    Filed: June 25, 2001
    Publication date: September 5, 2002
    Inventors: Tae Ho Cha, Se Aug Jang, Tae Kyun Kim, Dae Gyu Park, In Seok Yeo, Jin Won Park
  • Patent number: 6440827
    Abstract: A method for fabricating a wiring which runs at least piecewise in a substrate. At least one conductive connection runs in the semiconductor substrate and at least one conductive connection runs on the semiconductor substrate being provided. The semiconductor component enables applications in which high security against external manipulations is important.
    Type: Grant
    Filed: May 11, 2001
    Date of Patent: August 27, 2002
    Assignee: Infineon Technologies AG
    Inventors: Helga Braun, Ronald Kakoschke, Regina Stokan, Andreas Kux, Gunther Plasa
  • Publication number: 20020076876
    Abstract: A Method for manufacturing semiconductor devices having ESD protection. The method includes the steps of providing a semiconductor substrate having a well region, forming a gate structure on the semiconductor substrate, the gate structure including an oxide layer, a gate electrode on said oxide layer, and two spacer sidewalls, forming a source region within the well region at one side of the gate structure, forming a drain region within the well region at the other side of the gate structure, forming lightly doped source/drain regions in the well region and beneath the spacer walls of the gate structure wherein the lightly doped source/drain regions have the same conductivity type as the drain region and, and performing an implant with the same conductivity type as the well region as to form an ESD implantation region.
    Type: Application
    Filed: December 15, 2000
    Publication date: June 20, 2002
    Inventors: Ming-Dou Ker, Wen-Yu Lo, Peir-Jy Hu