Patents by Inventor Amitava Chatterjee
Amitava Chatterjee has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 6081002Abstract: A protection device for trench isolated technologies. The protection device includes a lateral SCR (100) that incorporates a triggering MOS transistor (120) with a first gate electrode (116) connected to the cathode (112) of the SCR (100). The anode (110) of the lateral SCR (100) is separated from the nearest source/drain region (122) of the triggering MOS transistor (120) by a second gate electrode (132) rather than by trench isolation. By using the second gate electrode (132) for isolation instead of trench isolation, the surface conduction of the lateral SCR (100) in unimpeded.Type: GrantFiled: May 27, 1998Date of Patent: June 27, 2000Assignee: Texas Instruments IncorporatedInventors: E. Ajith Amerasekera, Bernhard H. Andresen, Amitava Chatterjee
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Patent number: 6015992Abstract: A bistable SCR-like switch (41) protects a signal line (65) of an SOI integrated circuit (40) against damage from ESD events. The bistable SCR-like switch (41) is provided by a first and a second transistors (42 and 44) which are formed upon the insulator layer (46) of the SOI circuit (40) and are separated from one another by an insulating region (60). Interconnections (62 and 64) extend between the two transistors (42 and 44) to connect a P region (62) of a first transistor (42) to a P region (54) of the second transistor (44) and an N region (50) of the first transistor (42) to an N region (58) of the second transistor (44). The transistors (42 and 44) may be either bipolar transistors or enhancement type MOSFET transistors. For bipolar transistors, the base of an NPN transistor (42) is connected to the collector of a PNP transistor (44) and the base of the PNP transistor (44) is connected to the collector of the NPN transistor (42).Type: GrantFiled: December 30, 1997Date of Patent: January 18, 2000Assignee: Texas Instruments IncorporatedInventors: Amitava Chatterjee, Ekanayake Amerasekera
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Patent number: 5917219Abstract: A low power transistor (70, 70') formed in a face of a semiconductor layer (86) of a first conductivity type. The transistor includes a source and drain regions (76, 78) of a second conductivity type formed in the face of the semiconductor layer, and a gate (72) insulatively disposed adjacent the face of the semiconductor layer and between the source and drain regions. A layer of counter doping (80, 80') of the second conductivity type is formed adjacent to the face of the semiconductor layer generally between the source and drain regions. A first and second pockets (82, 84, 82', 84') of the first conductivity type may also be formed generally adjacent to the source and drain regions and the counter doped layer (80, 80').Type: GrantFiled: October 3, 1996Date of Patent: June 29, 1999Assignee: Texas Instruments IncorporatedInventors: Mahalingam Nandakumar, Amitava Chatterjee, Mark S. Rodder, Ih-Chin Chen
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Patent number: 5909628Abstract: A technique of producing a semiconductor device or integrated circuit produces a planarized refill layer which has a more uniform thickness after polishing, such as by chemical-mechanical polishing (CMP). Dummy active areas are inserted between active areas in that portion of the substrate which would normally be occupied by a field oxide in order to reduce to "dishing" that occurs during CMP in these areas. The dummy active areas can take the shape of a large block, a partially or completely formed ring structure or a plurality of pillars the area density of which can be adjusted to match the area density of the active areas in that region of the substrate. The design rule for the pillars can be such that no pillars are placed where polycrystalline silicon lines or first level metallization lines are to be placed in order to avoid parasitic capacitances.Type: GrantFiled: February 21, 1997Date of Patent: June 1, 1999Assignee: Texas Instruments IncorporatedInventors: Amitava Chatterjee, Theodore W. Houston, Ih-Chin Chen, Agerico L. Esquirel, Somnath Nag, Iqbal Ali, Keith A. Joyner, Yin Hu, Jeffrey Alan McKee, Peter Stewart McAnally
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Patent number: 5907462Abstract: A protection device comprising a gate-coupled silicon-controlled rectifier (SCR) (100), SCR (100) comprises an anode (105) formed in n-well (104) and connected to a pad (128) and a cathode (111) connected to ground. A gate-coupled NMOS transistor (120) has a gate (116) connected through a resistive element (118) to ground. A n+ region (112) forms both the cathode (111) and a source of the NMOS transistor (120). N-well (104) forms the drain. Stress voltage is coupled from pad (128) to gate electrode (116) causing NMOS transistor (120) to conduct. This, in turn, triggers SCR (100) which dissipates the stress current at the pad (128). The coupled voltage at gate electrode (116) dissipates within a designed time constant through resistive element (118).Type: GrantFiled: September 7, 1994Date of Patent: May 25, 1999Assignee: Texas Instruments IncorporatedInventors: Amitava Chatterjee, Charvaka Duvvury, Ping Yang, Ekanayake Ajith Amerasekera
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Patent number: 5822241Abstract: A pass transistor for a 1-transistor dynammic random access memory (DRAM) integrated circuit with a square root relation between threshold adjustment dose and substrate bias.Type: GrantFiled: July 29, 1997Date of Patent: October 13, 1998Assignee: Texas Instruments IncorporatedInventors: Amitava Chatterjee, Purnendu K. Mozumder
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Patent number: 5607867Abstract: An npn transistor having a low collector-base breakdown voltage. An emitter region (104, 106) of a first conductivity type is located in a semiconductor substrate (102). A base region (14) of a second conductivity type is located within the emitter region (104,106) and a shallow collector region (18) of the first conductivity type is located within the base region (14). The shallow collector region (18) may be doped with arsenic and/or phosphorus such that the dopant concentration and depth of the shallow collector region (18) provide a low collector-base breakdown voltage.Type: GrantFiled: June 7, 1995Date of Patent: March 4, 1997Assignee: Texas Instruments IncorporatedInventors: Ajith Amerasekera, Amitava Chatterjee
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Patent number: 5548548Abstract: A design to attain a pass transistor for a 256 Mbit DRAM part. The transistor having a gate length of about 0.3 .mu.m, a t.sub.ox of about 85 .ANG., which is much thicker than the .about.65 .ANG. t.sub.ox for 0.25 .mu.m logic technology, a V.sub.WL of 3.75 V, a V.sub.sub of -1 V, arsenic LDD and a boron concentration in the channel region of about 2.7.times.10.sup.17 /cm.sup.3 are the desired technological choices for 256 Mbit DRAM devices.Type: GrantFiled: December 19, 1994Date of Patent: August 20, 1996Assignee: Texas Instruments IncorporatedInventors: Amitava Chatterjee, Jiann Liu, Purnendu Mozumder, Mark S. Rodder, Ih-Chin Chen
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Patent number: 5539233Abstract: An npn transistor having a low collector-base breakdown voltage. An emitter region (104, 106) of a first conductivity type is located in a semiconductor substrate (102). A base region (14) of a second conductivity type is located within the emitter region (104,106) and a shallow collector region (18) of the first conductivity type is located within the base region (14). The shallow collector region (18) may be doped with arsenic and/or phosphorus such that the dopant concentration and depth of the shallow collector region (18) provide a low collector-base breakdown voltage.Type: GrantFiled: June 13, 1995Date of Patent: July 23, 1996Assignee: Texas Instruments IncorporatedInventors: Ajith Amerasekera, Amitava Chatterjee
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Patent number: 5517051Abstract: A first silicon controlled rectifier structure (220) is provided for electrostatic discharge protection, comprising a lightly doped semiconductor layer (222) having a first conductivity type and a face. A lightly doped region (224) having a second conductivity type opposite the first conductivity type is formed in the semiconductor layer (222) at the face. A first heavily doped region (226) having the second conductivity type is formed laterally within the semiconductor layer (222) at the face and is electrically coupled to a first node (62). A second heavily doped region (230) having the second conductivity type is formed laterally within the lightly doped region (224) and is electrically coupled to a second node (58). A third heavily doped region (228) having the first conductivity type is formed laterally within the lightly doped region (224) to be interposed between the first and second heavily doped regions (226 and 230) and is electrically coupled to the second node (58).Type: GrantFiled: January 20, 1995Date of Patent: May 14, 1996Assignee: Texas Insturments IncorporatedInventor: Amitava Chatterjee
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Patent number: 5465189Abstract: A new semiconductor controlled rectifier which may be used to provide on-chip protection against ESD stress applied at the input, output, power supply pins or between any arbitrary pair of pins of an integrated circuit is disclosed. The structure which has the lowest breakdown voltage for a given technology is incorporated into the SCR enabling a SCR trigger voltage determined by the lowest breakdown-structure.Type: GrantFiled: August 12, 1994Date of Patent: November 7, 1995Assignee: Texas Instruments IncorporatedInventors: Thomas L. Polgreen, Amitava Chatterjee, Ping Yang
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Patent number: 5453384Abstract: A first silicon controlled rectifier structure (220) is provided for electrostatic discharge protection, comprising a lightly doped semiconductor layer (222) having a first conductivity type and a face. A lightly doped region (224) having a second conductivity type opposite the first conductivity type is formed in the semiconductor layer (222) at the face. A first heavily doped region (226) having the second conductivity type is formed laterally within the semiconductor layer (222) at the face and is electrically coupled to a first node (62). A second heavily doped region (230) having the second conductivity type is formed laterally within the lightly doped region (224) and is electrically coupled to a second node (58). A third heavily doped region (228) having the first conductivity type is formed laterally within the lightly doped region (224) to be interposed between the first and second heavily doped regions (226 and 230) and is electrically coupled to the second node (58).Type: GrantFiled: March 25, 1994Date of Patent: September 26, 1995Assignee: Texas Instruments IncorporatedInventor: Amitava Chatterjee
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Patent number: 5225702Abstract: A first silicon controlled rectifier structure (220) is provided for electrostatic discharge protection, comprising a lightly doped semiconductor layer (222) having a first conductivity type and a face. A lightly doped region (224) having a second conductivity type opposite the first conductivity type is formed in the semiconductor layer (222) at the face. A first heavily doped region (226) having the second conductivity type is formed laterally within the semiconductor layer (222) at the face and is electrically coupled to a first node (62). A second heavily doped region (230) having the second conductivity type is formed laterally within the lightly doped region (224) and is electrically coupled to a second node (58). A third heavily doped region (228) having the first conductivity type is formed laterally within the lightly doped region (224) to be interposed between the first and second heavily doped regions (226 and 230) and is electrically coupled to the second node (58).Type: GrantFiled: December 5, 1991Date of Patent: July 6, 1993Assignee: Texas Instruments IncorporatedInventor: Amitava Chatterjee
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Patent number: 5068696Abstract: A programmable device (10) is formed from a silicided MOS transistor. The transistor (10) is formed at a face of a semiconductor layer (12), and includes a diffused drain region (17, 22) and a source region (19, 24) that are spaced apart by a channel region (26). At least the drain region (22) has a surface with a silicided layer (28) formed on a portion thereof. The application of a programming voltage in the range of ten to fifteen volts from the drain region (17, 22) to the source region (19, 24) has been discovered to reliably form a melt filament (40) across the channel region (26). A gate voltage (V.sub.g) may be applied to the insulated gate (14) over the channel region (26) such that a ten-volt programming voltage (V.sub.PROG) will cause melt filaments to form in those transistors to which the gate voltage is applied, but will not cause melt filaments to form in the remaining transistors (10) of an array.Type: GrantFiled: August 29, 1990Date of Patent: November 26, 1991Assignee: Texas Instruments IncorporatedInventors: Ping Yang, Amitava Chatterjee, Shian Aur, Thomas L. Polgreen
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Patent number: 5019878Abstract: A programmable device (10) is formed from a silicided MOS transistor. The transistor 10) is formed at a face of a semiconductor layer (12), and includes a diffused drain region (17, 22) and a source region (19, 24) that are spaced apart by a channel region (26). At least the drain region (22) has a surface with a silicided layer (28) formed on a portion thereof. The application of a programming voltage in the range of ten to fifteen volts from the drain region (17, 22) to the source region (19, 24) has been discovered to reliably form a melt filament (40) across the channel region (26). A gate voltage (V.sub.g) may be applied to the insulated gate (14) over the channel region (26) such that a ten-volt programming voltage (V.sub.PROG) will cause melt filaments to form in those transistors to which the gate voltage is applied, but will not cause melt filaments to form in the remaining transistors (10) of an array.Type: GrantFiled: March 31, 1989Date of Patent: May 28, 1991Assignee: Texas Instruments IncorporatedInventors: Ping Yang, Amitava Chatterjee, Shian Aur, Thomas L. Polgreen
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Patent number: 4896243Abstract: An efficient ESD protection circuit is provided having a resistor (18) disposed between an input pin (12) and the functioning circuitry (22) of an integrated circuit package. A primary switching device (28) is electrically connected between the input pin (12) and a reference voltage pin (14). The resistor (18) comprises an N- well (48) formed within the P- substrate (44) and an N+ diffused reion (50) formed within the N- well (48). A silicided layer (52) is formed over the N+ region (50). The primary switching device (28) is constructed to share the same PN junction (54) utilized by the resistor (18). In constructing the primary switching device (28), a P+ region (70) is formed within the N- well (48). Further, an N+ region (68) is formed within the P- substrate (44). Thus, the primary switching device (40) includes three PN junctions (72, 54, 74) which will conduct at a time prior to, or contemporaneous with, the breakdown of resistor (18).Type: GrantFiled: December 20, 1988Date of Patent: January 23, 1990Assignee: Texas Instruments IncorporatedInventors: Amitava Chatterjee, Charvaka Duvvury