With Means To Reduce Parasitic Capacitance Patents (Class 257/386)
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Patent number: 6043542Abstract: An integrated circuit structure for preventing latch-up of an integrated circuit device, such as a dynamic random access memory, that is operated with a negative substrate bias in use of the device. The integrated circuit structure includes a p-type substrate having an n-well region formed therein, with a rectifying junction formed in a lightly doped portion of the n-well region and connected to provide a path to ground for clamping the substrate to ground during power-up conditions. In another embodiment, a rectifying junction formed in a lightly doped portion of the n-well region functions as a diode clamp for a pumped bias voltage for the n-well region.Type: GrantFiled: January 29, 1997Date of Patent: March 28, 2000Assignee: Micron Technology, Inc.Inventors: Brent Keeth, Robert B. Kerr
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Patent number: 6040589Abstract: There is disclosed an active matrix liquid crystal display comprising pixels having an improved aperture ratio. A metallization layer makes contact with an active layer through openings. Inside the openings, the active layer is patterned into the same geometry as the metallization layer. That is, the active layer is patterned in a self-aligned manner according to the pattern of the metallization layer. This can enlarge the contact area. Also, the metallization layer does not required to be specially patterned for making contacts. A high aperture ratio can be obtained.Type: GrantFiled: June 12, 1997Date of Patent: March 21, 2000Assignee: Semiconductor Energy Laboratory Co., Ltd.Inventors: Hongyong Zhang, Jun Koyama, Satoshi Teramoto
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Patent number: 6034395Abstract: Arrangements are provided to increase the process control during the fabrication of the floating/control gate configuration in a non-volatile memory semiconductor device. The arrangements effectively reduce the severity of the topology attributable to the space between adjacent floating gates by advantageously reducing the height of the floating gates in particular locations. The reduced height floating gate's topology allows a subsequently formed control gate to be formed without significant surface depressions. Significant surface depressions in the control gate can lead to cracks in the silicide layer that is formed on the control gate. The cracking usually occurs during subsequent thermal processing of the semiconductor device. Thus the disclosed arrangements prevent cracking of the silicide layer on the control gate, which can affect the performance of the semiconductor device by increasing the resistance of the control gate arrangement.Type: GrantFiled: June 5, 1998Date of Patent: March 7, 2000Assignee: Advanced Micro Devices, Inc.Inventors: Nicholas H. Tripsas, Effiong Ibok, Tuan Duc Pham
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Patent number: 6020644Abstract: A semiconductor dynamic random access memory device has a switching transistor fabricated on a first area of a silicon substrate, another switching transistor fabricated on a second area of the silicon substrate and forming a part of a peripheral circuit, a first inter-level insulating structure covering the first and second switching transistors, a bit line formed on the first inter-level insulating structure and electrically connected to the drain region of the first switching transistor, a signal wiring layer formed on the first inter-level insulating structure and electrically connected to the drain region of the second switching transistor, a second inter-level insulating layer covering the bit line and the signal wiring layer and a storage capacitor formed on the second inter-level insulating layer and electrically connected to the drain region of the second switching transistor; parasitic capacitance is the major factor for the signal propagating speed along the bit line, and resistance is the major faType: GrantFiled: February 9, 1998Date of Patent: February 1, 2000Assignee: NEC CorporationInventor: Takaho Tanigawa
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Patent number: 6020617Abstract: A lateral MOS transistor is described, in particular, though not exclusively, a transistor of the lateral DMOS type, in which the drain is provided with a weakly doped drain extension (8) to increase the breakdown voltage. This drain extension is also present at the ends of the drain digits, so that the "hard" drain (5) does not continue up to the edge (7) of the active region (6), but is separated therefrom by an interposed region. These regions do not contribute to the transistor effect. To reduce parasitic input capacitances, which correspond to these non-active regions, the gate poly (9) is provided in the active portion of the transistor only and is replaced in the non-active portions by poly (22) which is connected through to the source (4, 16). This poly acts as a gate which is permanently at 0 V, so that leakage currents in the non-active regions are prevented.Type: GrantFiled: May 21, 1998Date of Patent: February 1, 2000Assignee: U.S. Philips CorporationInventor: Hendrikus F. F. Jos
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Patent number: 6001710Abstract: A method of fabricating a MOSFET transistor and resulting structure having a drain-gate feedback capacitance shield formed in a recess between a gate electrode and the drain region. The shield does not overlap the gate and thereby minimizes effect on the input capacitance of the transistor. The process does not require complex or costly processing since one additional non-critical mask is required with selective etch used to create the recess.Type: GrantFiled: March 30, 1998Date of Patent: December 14, 1999Assignee: Spectrian, Inc.Inventors: Hebert Francois, Szehim Ng
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Patent number: 5994202Abstract: A semiconductor MOSFET device is formed on a silicon substrate which includes trenches filled with Shallow Trench Isolation dielectric trench fill structures and extending above the surface of the substrate. The trench fill structures have protruding sidewalls with channel regions in the substrate having corner regions adjacent to the trench fill structures. The channel regions are between and adjacent to the STI trench fill structures doped with one concentration of dopant in the centers of the channel regions with a higher concentration of dopant in the corner regions. The dopant concentration differential provides a substantially equal concentration of electrons in the centers and at the corner regions of the channel regions.Type: GrantFiled: January 23, 1997Date of Patent: November 30, 1999Assignee: International Business Machines CorporationInventors: Jeffrey Peter Gambino, Gary Bela Bronner, Jack Allan Mandelman, Larry Alan Nesbit
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Patent number: 5977576Abstract: In an image sensor 1 wherein an N.sup.+ -type impurity layer 13 to become a light-receiving part of a first conductive type is formed in a well layer 12 of a second conductive type (P-type) provided in a semiconductor substrate 11 of the first conductive type (N-type), an N.sup.- -type impurity layer 14 whose impurity concentration is lower than that of the N.sup.+ -type impurity layer 13 and connected to the lower side of the N.sup.+ -type impurity layer 13 is provided between the N.sup.+ -type impurity layer 13 and the P-type well layer 12. Alternatively, a P-type impurity layer (not shown) whose impurity concentration is lower than that of the P-type well layer 12 and joining with the lower side of the N.sup.+ -type impurity layer 13 may be provided.Type: GrantFiled: February 20, 1997Date of Patent: November 2, 1999Assignee: Sony CorporationInventor: Masaharu Hamasaki
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Patent number: 5973364Abstract: An SOI-type MISFET with a body contact has a Si active layer arranged on an insulating layer. A pair of source and drain regions interposing a main channel region are arranged in the active layer. An additional channel region and a body-contact region are also arranged in the active layer. A gate electrode is arranged to have first and second portions facing the main and additional channel regions, respectively, through a gate insulating film. A main MIS capacitor and a parasitic MIS capacitor are formed under the first and second portions of the gate electrode, respectively. The additional channel region is doped with an impurity under a condition different from that of the main channel region such that electrical charges necessary for charging and discharging the parasitic MIS capacitor are decreased, in an operation voltage range of the device.Type: GrantFiled: September 18, 1998Date of Patent: October 26, 1999Assignee: Kabushiki Kaisha ToshibaInventor: Shigeru Kawanaka
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Patent number: 5939751Abstract: Disclosed is a MOSFET with double source and drain regions. Each of the source and drain regions in the MOSFET is implemented by two impurity-implanted regions. The source region has an n+ type region and a p type region which is formed beneath the n+ type region. The drain region has a p type region and an n+ type region which is formed beneath the p type region. Accordingly, the high built-in potential is induced in the source region and then the leakage current may decrease. On the other hand, because a current path is formed from the n+ type region in the source region to the n+ type region in the drain region, the hot carrier effect is reduced.Type: GrantFiled: June 13, 1997Date of Patent: August 17, 1999Assignee: Hyundai Electronics Industries Co., Ltd.Inventor: Kyeong Sik Jang
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Patent number: 5936289Abstract: A semiconductor device which solves the problem of parasitic substrate capacitance attenuating signal processing speed and reducing IC operating speed. An N-type semiconductor layer 12 is formed on a P-type semiconductor base 11, and an insulating film 13 and a pad 16 are formed on the semiconductor layer 12. A P-type isolating diffusion layer 20 is formed in part of the semiconductor layer 12 below the insulating film 13. An N-type impurity diffusion layer 17 connected to the semiconductor layer 12 is formed on the semiconductor layer 12, and an electrode 19 connected to the impurity diffusion layer 17 through a connecting hole 18 formed in the insulating film 13 above the impurity diffusion layer 17 is so formed that it is electrically independent from the pad 16.Type: GrantFiled: September 23, 1997Date of Patent: August 10, 1999Assignee: Sony CorporationInventor: Hideki Mori
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Patent number: 5932905Abstract: Ba--Sr--Ti-oxide dielectric material, with at least 60 atomic percent of the total content of the oxide being Ti, can have relatively high dielectric constant K (>40 at 20.degree. C.) and relatively low second order voltage coefficient a.sub.2 of the dielectric constant (a.sub.2 <100 PPM V.sup.2 at 20.degree. C.). In preferred embodiments the dielectric material has nominal composition (BA.sub.x Sr.sub.y Ti.sub.1--x--y)-oxide, with 1--x--y in the range 0.65-0.90, with both x and y greater than or equal to 0.05. Ba, Sr and Ti together typically comprise at least 99 atomic percent of the total metal content of the dielectric material.Type: GrantFiled: November 26, 1997Date of Patent: August 3, 1999Assignees: Lucent Technologies Inc., Advanced Technology Materials, Inc.Inventors: Henry Miles O'Bryan, Jr., Jeffrey Frederick Roeder, Gregory T. Stauf, Roderick Kent Watts
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Patent number: 5861653Abstract: An inter-level insulating structure is formed by a lower silicon oxide layer, an upper silicon oxide layer and an air layer filling a gap between the lower silicon oxide layer and the upper silicon oxide layer, and the air layer decreases the effective dielectric constant so that a parasitic capacitance across the inter-level insulating structure is drastically decreased.Type: GrantFiled: May 10, 1996Date of Patent: January 19, 1999Assignee: NEC CorporationInventor: Hiromitsu Hada
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Patent number: 5861652Abstract: The present invention provides an integrated circuit chip having one or more circuit elements that perform a desired circuit function with the circuit elements being encompassed by a molding compound that forms a package for the chip. The molding compound has a capacitance associated with it. The integrated circuit chip includes a second integrated circuit element within the molding compound in which the second integrated circuit element monitors the molding compound to detect a change in capacitance in the molding compound resulting from a removal of a portion or all of the molding compound. In response to a detection of a change in capacitance, the second integrated circuit element alters the desired circuit function provided by the other integrated circuit elements.Type: GrantFiled: March 28, 1996Date of Patent: January 19, 1999Assignee: Symbios, Inc.Inventors: Richard K. Cole, James P. Yakura
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Patent number: 5814848Abstract: In a semiconductor integrated circuit, the wiring capacitance of the bus line region is reduced, so that the operation speed can be increased, the power consumption can be decreased, and the chip size can be reduced. On the upper surface of the field oxide film (4) formed on the semiconductor substrate (8), a non-conductive insulating oxide film (12) is formed by oxidizing the poly silicon layer (9). Further, the bus lines (3A) are formed on the oxide film (12) via the interlayer insulating film (6). Therefore, a distance between the bus lines (3A) and the substrate (8) can be increased to decrease the capacitance of the bus lines (3A).Type: GrantFiled: May 31, 1996Date of Patent: September 29, 1998Assignee: Kabushiki Kaisha ToshibaInventor: Shigeo Oshima
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Patent number: 5814869Abstract: A Fermi-threshold field effect transistor includes spaced-apart source and drain regions which extend beyond the Fermi-tub in the depth direction and which may also extend beyond the Fermi-tub in the lateral direction. In order to compensate for the junction with the substrate, the doping density of the substrate region is raised to counteract the shared charge. Furthermore, the proximity of the source and drain regions leads to a potential leakage due to the drain field which can be compensated for by reducing the maximum tub depth compared to a low capacitance Fermi-FET and a contoured-tub Fermi-FET while still satisfying the Fermi-FET criteria. The tub depth is maintained below a maximum tub depth. Short channel effects may also be reduced by providing source and drain extension regions in the substrate, adjacent the source and drain regions and extending towards the channel regions.Type: GrantFiled: July 21, 1995Date of Patent: September 29, 1998Assignee: Thunderbird Technologies, Inc.Inventor: Michael W. Dennen
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Patent number: 5801398Abstract: A field effect transistor including a gate electrode, a semiconductor region, a source electrode and a drain electrode, the source and drain electrodes being formed on opposite sides of the semiconductor region and spaced apart from the gate electrode. The semiconductor region is formed such that the source and drain electrodes are in direct contact with ends of the semiconductor region, and a channel region is formed through the semiconductor region in response to a voltage applied to the gate electrode, the channel region extending from the source electrode to the drain electrode. Junctions between the source and drain electrodes and the semiconductor region are formed as an insulated area including a schottky barrier. The source and drain electrodes either have a work function which is greater than the work function of the semiconductor region (for p-channel transistors), or a work function which is less than the work function of the semiconductor region (for n-channel transistors).Type: GrantFiled: October 17, 1995Date of Patent: September 1, 1998Assignee: Frontec CorporationInventor: Hiroyuki Hebiguchi
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Patent number: 5801426Abstract: The invention provides a diffusion region structure in a semiconductor device wherein the diffusion region is applied with alternating voltages in an operation of the semiconductor device. The structure comprises at least one diffusion region being doped with an impurity of a first conductivity type at a first impurity concentration and also being provided in a semiconductor bulk region doped with an impurity of a second conductivity type at a second impurity concentration lower than the first impurity concentration, and at least a diffusion capacitance reduction layer provided under the diffusion region so as to be in contact with a bottom of the diffusion region.Type: GrantFiled: August 16, 1995Date of Patent: September 1, 1998Assignee: NEC CorporationInventor: Ryuichi Okamura
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Patent number: 5789818Abstract: A semiconductor device and method having a low-permittivity material between closely-spaced leads in order to decrease unwanted capacitance, while having a more structurally strong dielectric between widely-spaced leads where capacitance is not as critical. Metal layer 14 is deposited on a substrate 12 of a semiconductor wafer 10, where the metal layer 14 has a first portion 15 and a second portion 17. Widely-spaced leads 16 are formed in the first portion 15 of the metal layer 14, and a first structural dielectric layer 26 is deposited on at least the widely-spaced leads. Closely-spaced leads 18 are formed in the second portion 17 of the metal layer 14, and low-permittivity material 34 is deposited between closely-spaced leads 18. A second structural dielectric layer 36 is deposited on at least low-permittivity material 34 and closely-spaced leads 18.Type: GrantFiled: June 21, 1996Date of Patent: August 4, 1998Assignee: Texas Instruments IncorporatedInventor: Robert H. Havemann
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Patent number: 5789791Abstract: The gate resistance of a high-frequency multi-finger MOS transistor is reduced by shorting together the ends of each of the gates by utilizing gate contacts, metal regions, vias, and a metal layer. Alternately, the gate resistance is reduced by utilizing a metal line that shorts all of the gate contacts together, and overlies each of the gates. By reducing the gate resistance, the maximum frequency f.sub.MAX of the multi-finger transistor can be increased.Type: GrantFiled: November 15, 1996Date of Patent: August 4, 1998Assignee: National Semiconductor CorporationInventor: Albert M. Bergemont
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Patent number: 5783849Abstract: On a semiconductor substrate (1) is provided an insulator film, on which is formed a lower gate electrode including a first lower gate electrode (5a) and a second lower gate electrode (5b), on which lower gate electrode is formed a lower gate insulator film. On the lower gate insulator film is disposed a device region (9), on which is disposed an upper gate electrode (13) by way of an upper gate insulator film. The device region (9) has island-shaped patterns. The first lower gate electrode (5a) is placed in substantially the middle part of the device region (9), while the second lower gate electrode (5b) is provided in parallel with the first lower gate electrode (5a) and at a boundary between the device region (9) and the insulator film. The upper gate electrode (13) is positioned orthogonal to the lower gate electrodes (5a, 5b). This configuration will make it possible to inhibit the occurrence of current leakage due to parasitic transistors.Type: GrantFiled: February 21, 1997Date of Patent: July 21, 1998Assignee: Citizen Watch Co., Ltd.Inventors: Toshiyuki Kishi, Takashi Toida
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Patent number: 5767542Abstract: A CMOS layout enables the matching of an intentionally created parasitic capacitance to an existing parasitic capacitance, for example, a gate-to-drain capacitance of a MOSFET, with a high degree of precision. This precise matching allows a differential pair of MOSFETs acting as the input of an amplfier to have intentionally created capacitances (that match the parasitic gate-to-drain capacitances) cross-coupled between the inputs and the outputs of the differential pair. This cross-coupling of matching capacitances effectively cancels the bandwidth reducing effect of the gate-to-drain capacitances of the differential pair. The layout provides for the interdigitation of the gates of the differential pair, with each input transistor comprising at least two transistors connected together to form a single input transistor.Type: GrantFiled: May 28, 1996Date of Patent: June 16, 1998Assignee: Analog Devices, Inc.Inventor: Katsufumi Nakamura
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Patent number: 5763924Abstract: A simple, low-cost circuit and method for line zing parasitic capacitances of transistor junctions, independent of the process technology employed, are provided. In the preferred embodiment, the parasitic capacitance of a transistor in a track and hold circuit is linearized by providing a pair of diodes that act inversely to the parasitic diodes formed within the integrated circuit during normal tracking operations. Without the diodes of the present invention, the varying input signals cause the parasitic capacitance to vary, thereby causing harmonic distortion in the track and hold circuit. An alternate embodiment of the present invention is also provided in which a second complementary transistor is provided. The inclusion of the complementary transistor results in a second set of parasitic capacitances that are substantially opposite the parasitic capacitances of the track and hold transistor.Type: GrantFiled: May 9, 1996Date of Patent: June 9, 1998Assignee: Linear Technology CorporationInventors: Sammy S. Lum, William C. Rempfer
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Patent number: 5760452Abstract: Disclosed are an improved semiconductor memory cell suitable for high integration and a novel method of fabricating the same. The memory cell has a large capacitance and a small area. The memory cell also has a plurality of bit-lines buried in an isolation region in a semiconductor substrate. The bit-line has a very small width and thickness thereby reducing a parasitic capacity between the bit-line and the semiconductor substrate. The memory cell may further be provided with a noise shielding line. Further, disclosed is a novel memory cell array of a semiconductor memory. The buried bit-line is coupled with a bit-line connecting sub-arrays and both are separated by a insulation film. A plurality of pairs of the bit-lines are arranged in rows. A word-line is coupled with a sub-word line and both are separated by a insulation film. A plurality of pairs of the word-lines are arranged in columns. The memory cells are arranged at the intersections of the buried bit-lines and the word-lines.Type: GrantFiled: October 15, 1996Date of Patent: June 2, 1998Assignee: NEC CorporationInventor: Kazuo Terada
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Patent number: 5753958Abstract: An adjustable threshold voltage MOS device having an asymmetric pocket region is disclosed herein. The pocket region abuts one of a source or drain proximate the device's channel region. The pocket region has the same conductivity type as the device's bulk (albeit at a higher dopant concentration) and, of course, the opposite conductivity type as the device's source and drain. An MOS device having such pocket region may have its threshold voltage adjusted by applying a potential directly to its pocket region. This capability is realized by providing a contact or conductive tie electrically coupled to the pocket region. This "pocket tie" is also electrically coupled to a metallization line (external to the device) which can be held at a specified potential corresponding to a potential required to back-bias the device by a specified amount.Type: GrantFiled: October 16, 1995Date of Patent: May 19, 1998Assignee: Sun Microsystems, Inc.Inventors: James B. Burr, Douglas Alan Laird
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Patent number: 5731620Abstract: An N-type semiconductor layer 12 is formed on a P-type semiconductor base 11, and an insulating film 13 and a pad 16 are formed on the semiconductor layer 12. A P-type isolating diffusion layer 20 is formed in part of the semiconductor layer 12 below the insulating film 13. An N-type impurity diffusion layer 17 connected to the semiconductor layer 12 is formed on the semiconductor layer 12, and an electrode 19 connected to the impurity diffusion layer 17 through a connecting hole 18 formed in the insulating film 13 above the impurity diffusion layer 17 is so formed that it is electrically independent from the pad 16. The isolating diffusion layer 20 is formed outside the outer periphery of the impurity diffusion layer 17 and so that the PN junction between the semiconductor base 11 and the semiconductor layer 12 exists in at least a part of the area below the pad 16.Type: GrantFiled: September 5, 1996Date of Patent: March 24, 1998Assignee: Sony CorporationInventor: Hideki Mori
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Patent number: 5717251Abstract: After a pattern transfer of a first pattern image to a lower photo-sensitive layer of first material, a second pattern image is transferred to an upper photo-sensitive layer of second material higher in photo-sensitivity than the first material, and the first image and the second image are concurrently developed so as to form a composite etching mask through a simple process.Type: GrantFiled: August 5, 1996Date of Patent: February 10, 1998Assignee: NEC CorporationInventors: Yoshihiro Hayashi, Takahiro Onodera
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Patent number: 5717242Abstract: An integrated circuit is provided having an improved interconnect structure. The interconnect structure includes a power-coupled local interconnect which is always retained at VDD or VSS (i.e., ground) level. The local interconnect resides a dielectric-spaced distance below critical runs of overlying interconnect. The powered local interconnect serves to sink noise transients from the critical conductors to ensure that circuits connected to the conductors do not inoperably function. Accordingly, the local interconnect extends along a substantial portion of the conductor length, and is either wider or narrower than the conductor under which it extends. The local interconnect can either be polysilicon, doped polysilicon, polycide, refractory metal silicide, or multi-level refractory metal.Type: GrantFiled: April 17, 1996Date of Patent: February 10, 1998Assignee: Advanced Micro Devices, Inc.Inventors: Mark W. Michael, Robert Dawson, Basab Bandyopadhyay, H. Jim Fulford, Jr., Fred N. Hause, William S. Brennan
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Patent number: 5682323Abstract: The system and method performs optical proximity correction on an integrated circuit (IC) mask design by initially performing optical proximity correction on a library of cells that are used to create the IC. The pre-tested cells are imported onto a mask design. All cells are placed a minimum distance apart to ensure that no proximity effects will occur between elements fully integrated in different cells. An optical proximity correction technique is performed on the mask design by performing proximity correction only on those components, e.g., lines, that are not fully integrated within one cell.Type: GrantFiled: March 6, 1995Date of Patent: October 28, 1997Assignee: LSI Logic CorporationInventors: Nicholas Pasch, Nicholas Eib, Jeffrey Dong
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Patent number: 5670815Abstract: A layout portion (20) has a first portion (25), and a second portion (55). In the first portion (25), a reference voltage line (27) is disposed between two V.sub.DD power supply lines (26, 30) for a first predetermined length, for providing capacitive coupling between V.sub.DD and a reference voltage. In the second portion (55), the reference voltage line (27) is disposed between two V.sub.SS power supply lines (28, 41) for a second predetermined length, for providing capacitive coupling between V.sub.SS and the reference voltage. The capacitive coupling stabilizes the reference voltage with respect to the power supply voltage, and reduces power supply noise due to lead inductance and changing current demand. In addition, the power supply lines (26, 28, 30, 41) are disposed half above an N-type region (22) and half above a P-type substrate (21) for reducing local transistor switching noise.Type: GrantFiled: July 5, 1994Date of Patent: September 23, 1997Assignee: Motorola, Inc.Inventors: Lawrence F. Childs, Stephen T. Flannagan, Ray Chang, Donovan L. Raatz
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Patent number: 5663588Abstract: A semiconductor device of SOI structure formed by the mesa isolation method, which can sufficiently reduce the wiring capacitance even if the width of the isolation trench is large. An SOI layer which constitutes an element region is formed by forming a buried oxide film in a silicon substrate, forming an isolation trench in the buried oxide film and burying an isolating material in the isolation trench. By the formation of the SOI layer with the isolating material, a dummy SOI layer is formed in a field part other than the element region. Then, by the formation of a MOSFET gate wiring on the dummy SOI layer, the wiring capacitance is reduced. Furthermore, the dummy SOI layer is completely depleted when the MOSFET threshold value is applied to the gate wiring.Type: GrantFiled: July 11, 1995Date of Patent: September 2, 1997Assignee: Nippondenso Co., Ltd.Inventors: Megumi Suzuki, Kazuhiro Tsuruta, Akiyoshi Asai
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Patent number: 5635747Abstract: A nonvolatile semiconductor memory with a unit cell structure suitable for high speed operation and a low power supply voltage. The nonvolatile semiconductor memory includes a switching circuit including block select transistors connected by its respective terminal to a corresponding bit line. This switching circuit transmits a signal only when a string to which the switching circuit corresponds is selected. A second active region having a different impurity concentration from a first active region constituting source and drain regions of memory transistors is formed at a substrate contact portion of a bit line contact portion where the memory string and bit line are connected. The impurity concentration of the second active region is lower than that of the first active region.Type: GrantFiled: June 7, 1995Date of Patent: June 3, 1997Assignee: Samsung Electronics Co., Ltd.Inventors: Hyong-Gon Lee, Sang-Ki Hwang, Cheol-Ung Jang, Young-Wi Ko, Sung-Hee Cho
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Patent number: 5614750Abstract: A buried layer contact for a integrated circuit structure is provided, with particular application for a contact for a buried collector of a bipolar transistor. The buried layer contact takes the form of a sinker comprising a fully recessed trench isolated structure having dielectric lined sidewalls and filled with conductive material, e.g. doped polysilicon which contacts the buried layer. The trench isolated contact is more compact than a conventional diffused sinker structure, and thus beneficially allows for reduced transistor area. Advantageously, a reduced area sinker reduces the parasitic capacitance and power dissipation. In a practical implementation, the structure provides for an annular collector contact structure to reduce collector resistance.Type: GrantFiled: June 29, 1995Date of Patent: March 25, 1997Assignee: Northern Telecom LimitedInventors: Joseph P. Ellul, John M. Boyd
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Patent number: 5610430Abstract: The semiconductor device of the invention includes: a semiconductor substrate of a first conductivity type; a gate insulating film formed on a selected region on a main surface of the semiconductor substrate; a gate electrode formed on the gate insulating film; and a source region and a drain region which are formed of high-concentration impurity diffusion layers of a second conductivity type in the semiconductor substrate. In the semiconductor device, a thickness of both end portions of the gate insulating film is larger than a thickness of a center portion of the gate insulating film, and each of the source region and the drain region includes a first portion located under both end-portions of the gate insulating film and a second portion having a thickness equal to or larger than a thickness of the first portion. An impurity concentration in the first portion is substantially equal to an impurity concentration in the second portion.Type: GrantFiled: June 26, 1995Date of Patent: March 11, 1997Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Kyoji Yamashita, Shinji Odanaka, Kazumi Kurimoto, Hiroyuki Umimoto
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Patent number: 5600163Abstract: A field-effect semiconductor element implemented with a fewer number of elements and a reduced area and capable of storing data by itself without need for cooling at a cryogenic temperature, and a memory device employing the same. Gate-channel capacitance is set so small that whether or not a trap captures one electron or hole can definitely and distinctively be detected in terms of changes of a current of the semiconductor FET element. By detecting a change in a threshold voltage of the semiconductor element brought about by trapping of electron or hole in the trap, data storage can be realized at a room temperature.Type: GrantFiled: August 16, 1994Date of Patent: February 4, 1997Assignee: Hitachi, Ltd.Inventors: Kazuo Yano, Tomoyuki Ishii, Takashi Hashimoto, Koichi Seki, Masakazu Aoki, Takeshi Sakata, Yoshinobu Nakagome, Kan Takeuchi
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Patent number: 5583361Abstract: A semiconductor device is provided with a semiconductor at least including a source and a drain of a conductive type with a high impurity concentration and a channel area of a second conductive type opposite to the first conductive type, positioned between the source and drain, an insulation layer covering at least the channel area, and a gate electrode of a conductive material positioned adjacent to the insulation layer. A pn junction is positioned below the insulated gate electrode. A depletion layer extending from the pn junction at least reaches the source and drain areas.Type: GrantFiled: December 1, 1994Date of Patent: December 10, 1996Assignee: Canon Kabushiki KaishaInventor: Masakazu Morishita
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Patent number: 5548150Abstract: A high-resistant p-silicon layer is formed on a silicon substrate through a silicon oxide film. N-source and n-drain layers are selectively formed in the surface of the high-resistant p-silicon layer. A gate electrode is formed through a gate insulating film on a channel region between the source and drain layers. To induce an n-inverted layer under the gate electrode, a p-base layer is formed in the high-resistant p-silicon layer. A depletion layer extending from a pn junction between the n-drain layer and the high-resistant p-silicon layer reaches the silicon oxide film in a thermal equilibrium state. Part of the high-resistant p-silicon layer extends into a channel region between the drain and base layers. The drain and base layers are connected to each other through part of the depletion layer in the thermal equilibrium state. A field effect transistor having a high-speed operation is provided.Type: GrantFiled: April 17, 1995Date of Patent: August 20, 1996Assignee: Kabushiki Kaisha ToshibaInventors: Ichiro Omura, Akio Nakagawa, Tadashi Sakai, Masayuki Sekimura, Hideyuki Funaki
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Patent number: 5543654Abstract: A Fermi-threshold field effect transistor includes a contoured-tub region of the same conductivity type as the source, drain and channel regions and having nonuniform tub depth. The contoured-tub is preferably deeper under the source and/or drain regions than under the channel region. Thus, the tub-substrate junction is deeper under the source and/or drain regions than under the channel region. The diffusion capacitance is thereby reduced compared to a tub having a uniform tub depth, so that a high saturation current is produced at low voltages. The contoured-tub may be formed by an additional implant into the substrate using the gate as a mask.Type: GrantFiled: December 7, 1994Date of Patent: August 6, 1996Assignee: Thunderbird Technologies, Inc.Inventor: Michael W. Dennen
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Patent number: 5471419Abstract: A semiconductor device having a programmable memory cell which includes a bipolar transistor of which a base region (13) can be provided with a base current through a control transistor (7, 8, 9, 10). The bipolar transistor has an emitter region (12) connected to a first supply line (151) and has a collector region (14) connected to a second supply line (152) through a load (16). A constant potential difference is maintained between the two supply lines (151, 152) during operation. The collector region (14) is laterally electrically insulated and provides a feedback to the control transistor in such a manner that, during operation within a certain voltage domain, a change in the voltage difference between the emitter region (12) and the collector region (14) leads to an opposite change in the conductivity through the control transistor.Type: GrantFiled: April 22, 1994Date of Patent: November 28, 1995Assignee: U.S. Philips CorporationInventors: Lakshmi N. Sankaranarayanan, Jan W. Slotboom, Arjen G. Van Der Sijde
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Patent number: 5444288Abstract: An important problem in large integrated circuits is constituted by noise superimposed on the supply. This noise is particularly caused by switching of switching elements such as flipflops, and by heavily loaded output stages. These elements cause current peaks which may give rise to comparatively great fluctuations in voltage. This problem is solved at least to a great extent in CMOS circuits with standard cells or with custom layout blocks by means of an additional decoupling capacitance in the form of an extra well in the routing channels. The decoupling capacitance may be positioned immediately adjacent the switching element, which is favorable for suppressing the supply noise. Since the routing channels are generally not used for providing circuit elements, the chip surface area is not or substantially not increased by this extra capacitance.Type: GrantFiled: July 1, 1994Date of Patent: August 22, 1995Assignee: U.S. Philips CorporationInventor: Eino Jacobs
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Patent number: 5374836Abstract: A high current Fermi-FET includes an injector region of the same conductivity type as the Fermi-Tub region and the source and drain regions, located adjacent the source region and facing the drain region. The injector region is preferably doped at a doping level which is intermediate the relatively low doping concentration of the Fermi-Tub and the relatively high doping concentration of the source region. The injector region controls the depth of the carriers injected into the channel and maximizes injection of carriers into the channel at a predetermined depth below the gate. The injector region may also extend to the Fermi-tub depth to decrease bottom leakage current. Alternatively, a bottom leakage current control region may be used to decrease bottom leakage current. Lower pinch-off voltage and increased saturation current are obtained by providing a gate sidewall spacer which extends from adjacent the source injector region to adjacent the sidewall of the polysilicon gate electrode of the Fermi-FET.Type: GrantFiled: February 23, 1993Date of Patent: December 20, 1994Assignee: Thunderbird Technologies, Inc.Inventors: Albert W. Vinal, Michael W. Dennen
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Patent number: 5355006Abstract: A semiconductor memory device comprises a semiconductor substrate, a plurality of memory cells each comprised of a cell transistor having at least a pair of source and drain regions formed in the semiconductor substrate and a gate electrode formed thereon, a bit line, a bit contact for providing contact between the drain region and the bit line, a capacitor and a storage contact for providing contact between the source region and the capacitor, in which the pair of source and drain regions are disposed in limited areas near the gate electrode and independent form not sharing those in other memory cells.Type: GrantFiled: February 25, 1994Date of Patent: October 11, 1994Assignee: Sharp Kabushiki KaishaInventor: Katsuji Iguchi
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Patent number: 5304835Abstract: A semiconductor device comprising a memory cell matrix array wherein transistors formed on the outer edge of the memory cell matrix array are inferior in performance compared to the transistors comprising the operating memory cell matrix array because their transistor active regions shrink during semiconductor device fabrication. To avoid this problem, a dummy region is formed around the operating memory cell matrix array. The dummy region contains impurity regions formed at substantially the same density as the transistors comprising the operating memory cell matrix array. Thus, the transistors located on the outer edge of the operating memory cell matrix array function in the same manner as transistors formed within the operating memory cell matrix array. As a result, all the transistors of the operating memory cell matrix array have uniform performance.Type: GrantFiled: May 18, 1992Date of Patent: April 19, 1994Assignee: Seiko Epson CorporationInventors: Kaori Imai, Noboru Itomi
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Patent number: 5264385Abstract: A novel layout performing SRAM cells is disclosed wherein conductive straps (36) connect first and second driver gates (22, 24) to second and first drains (33, 31) respectively without connecting the moat of one cell with the moat of another cell such that the conductive straps are never in a DC current path.Type: GrantFiled: December 9, 1991Date of Patent: November 23, 1993Assignee: Texas Instruments IncorporatedInventor: Mark S. Rodder
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Patent number: 5262672Abstract: A method and apparatus for reducing interconnection capacitance. A lightly doped buried layer is provided in or on a substrate below a field oxide region. The capacitance of an interconnect on the field oxide is significantly reduced by the lightly doped buried layer. When using a p-type substrate, the lightly doped buried layer may, for example, be a lightly doped (10.sup.13 /cm.sup.3) n-type region. Junction capacitance of, for example, a bipolar transistor is also reduced.Type: GrantFiled: November 27, 1991Date of Patent: November 16, 1993Assignee: National Semiconductor CorporationInventor: Ali A. Iranmanesh
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Patent number: 5223733Abstract: A semiconductor integrated circuit device is provided which include a plurality of cell columns each having a number of unit cells previously fabricated on a semiconductor substrate selected from the plural kinds of unit cells which are formed in desired circuits by electrically connecting circuit devices previously arranged. Each column includes at least one kind of unit cell of a dynamic circuit which has a node in a floating state during the operation of the cell unit. A fixed potential shield layer is also provided on the cell columns so as to cover the nodes of the dynamic circuits. By virtue of this, a wiring area for electrically connecting the desired cell units can be located between the cell columns and above the shield layer. In other words, signal wirings in the wiring area can pass over the nodes of the dynamic circuits. without adverse parasitic effects. The unit cell can also be provided with a precharge circuit comprising a standard cell and an in-cell wiring layer.Type: GrantFiled: November 14, 1991Date of Patent: June 29, 1993Assignee: Hitachi, Ltd.Inventors: Toshio Doi, Takehisa Hayashi, Kenichi Ishibashi, Mitsuo Asai