Patents by Inventor Xiaoju Wu
Xiaoju Wu 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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Publication number: 20110110160Abstract: Electrically erasable programmable “read-only” memory (EEPROM) cells in an integrated circuit, and formed by a single polysilicon level. The EEPROM cell consists of a coupling capacitor and a combined read transistor and tunneling capacitor. The capacitance of the coupling capacitor is much larger than that of the tunneling capacitor. In one embodiment, field oxide isolation structures isolate the devices from one another; a lightly-doped region at the source of the read transistor improves breakdown voltage performance. In another embodiment, trench isolation structures and a buried oxide layer surround the well regions at which the coupling capacitor and combined read transistor and tunneling capacitor are formed.Type: ApplicationFiled: January 11, 2011Publication date: May 12, 2011Applicant: TEXAS INSTRUMENTS INCORPORATEDInventors: Xiaoju Wu, Jozef Czeslaw Mitros
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Patent number: 7919368Abstract: Electrically erasable programmable “read-only” memory (EEPROM) cells in an integrated circuit, and formed by a single polysilicon level. The EEPROM cell consists of a coupling capacitor and a combined read transistor and tunneling capacitor. The capacitance of the coupling capacitor is much larger than that of the tunneling capacitor. In one embodiment, field oxide isolation structures isolate the devices from one another; a lightly-doped region at the source of the read transistor improves breakdown voltage performance. In another embodiment, trench isolation structures and a buried oxide layer surround the well regions at which the coupling capacitor and combined read transistor and tunneling capacitor are formed.Type: GrantFiled: May 29, 2009Date of Patent: April 5, 2011Assignee: Texas Instruments IncorporatedInventors: Xiaoju Wu, Jozef C. Mitros
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Patent number: 7893768Abstract: A method and system for providing automatic gain control for a differential amplifier are provided. An impedance network is set to have a first impedance that corresponds to a first gain for a differential amplifier, which amplifies an input signal by the first gain. Once the amplified input signal is greater than a first threshold voltage, the impedance network is set to have a second impedance that corresponds to a second gain for the differential amplifier, which amplifies the input signal. Once amplified input signal is greater than a second threshold voltage and a predetermined period has lapsed, the impedance network is reset to have the first impedance that corresponds to a first gain for the differential amplifier.Type: GrantFiled: March 10, 2009Date of Patent: February 22, 2011Assignee: Texas Instruments IncorporatedInventors: Zhengyu Wang, Xiaoju Wu
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Publication number: 20100302854Abstract: Electrically erasable programmable “read-only” memory (EEPROM) cells in an integrated circuit, and formed by a single polysilicon level. The EEPROM cell consists of a coupling capacitor and a combined read transistor and tunneling capacitor. The capacitance of the coupling capacitor is much larger than that of the tunneling capacitor. In one embodiment, field oxide isolation structures isolate the devices from one another; a lightly-doped region at the source of the read transistor improves breakdown voltage performance. In another embodiment, trench isolation structures and a buried oxide layer surround the well regions at which the coupling capacitor and combined read transistor and tunneling capacitor are formed.Type: ApplicationFiled: May 29, 2009Publication date: December 2, 2010Applicant: TEXAS INSTRUMENTS INCORPORATEDInventors: Xiaoju Wu, Jozef Czeslaw Mitros
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Publication number: 20100264466Abstract: The disclosure herein pertains to fashioning a low noise junction field effect transistor (JFET) where transistor gate materials are utilized in forming and electrically isolating active areas of a the JFET. More particularly, active regions are self aligned with patterned gate electrode material and sidewall spacers which facilitate desirably locating the active regions in a semiconductor substrate. This mitigates the need for additional materials in the substrate to isolate the active regions from one another, where such additional materials can introduce noise into the JFET. This also allows a layer of gate dielectric material to remain over the surface of the substrate, where the layer of gate dielectric material provides a substantially uniform interface at the surface of the substrate that facilitates uninhibited current flow between the active regions, and thus promotes desired device operation.Type: ApplicationFiled: June 29, 2010Publication date: October 21, 2010Applicant: TEXAS INSTRUMENTS INCORPORATEDInventors: Xiaoju Wu, Fan-Chi Frank Hou, Pinghai Hao
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Publication number: 20100231299Abstract: A method and system for providing automatic gain control for a differential amplifier are provided. An impedance network is set to have a first impedance that corresponds to a first gain for a differential amplifier, which amplifies an input signal by the first gain. Once the amplified input signal is greater than a first threshold voltage, the impedance network is set to have a second impedance that corresponds to a second gain for the differential amplifier, which amplifies the input signal. Once amplified input signal is greater than a second threshold voltage and a predetermined period has lapsed, the impedance network is reset to have the first impedance that corresponds to a first gain for the differential amplifier.Type: ApplicationFiled: March 10, 2009Publication date: September 16, 2010Applicant: Texas Instrument IncorporatedInventors: Zhengyu Wang, Xiaoju Wu
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Patent number: 7785906Abstract: A test structure which can be used to detect residual conductive material such as polysilicon which can result from an under etch comprises a PMOS transistor and an OTP EPROM floating gate device. By testing the devices using different testing parameters, it can be determined whether residual conductive material remains subsequent to an etch, and where the residual conductive material is located on the device. A method for testing a semiconductor device using the test structure is also described.Type: GrantFiled: December 12, 2007Date of Patent: August 31, 2010Assignee: Texas Instruments IncorporatedInventors: Xiaoju Wu, Jozef Czeslaw Mitros
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Publication number: 20100164004Abstract: A method of fabricating an integrated circuit (IC) including a plurality of MOS transistors and ICs therefrom include providing a substrate having a silicon including surface, and forming a plurality of dielectric filled trench isolation regions in the substrate, wherein the silicon including surface forms trench isolation active area edges along its periphery with the trench isolation regions. A first silicon including layer is deposited, wherein the first silicon including extends from a surface of the trench isolation regions over the trench isolation active area edges to the silicon including surface. The first silicon including layer is completely oxidized to convert the first silicon layer to a silicon oxide layer, wherein the silicon oxide layer provides at least a portion of a gate dielectric for at least one of the plurality of MOS transistors.Type: ApplicationFiled: December 29, 2008Publication date: July 1, 2010Applicant: TEXAS INSTRUMENTS INCORPORATEDInventors: AMITAVA CHATTERJEE, SEETHARAMAN SRIDHAR, XIAOJU WU, VLADIMIR F. DROBNY
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Patent number: 7745274Abstract: The disclosure herein pertains to fashioning a low noise junction field effect transistor (JFET) where transistor gate materials are utilized in forming and electrically isolating active areas of a the JFET. More particularly, active regions are self aligned with patterned gate electrode material and sidewall spacers which facilitate desirably locating the active regions in a semiconductor substrate. This mitigates the need for additional materials in the substrate to isolate the active regions from one another, where such additional materials can introduce noise into the JFET. This also allows a layer of gate dielectric material to remain over the surface of the substrate, where the layer of gate dielectric material provides a substantially uniform interface at the surface of the substrate that facilitates uninhibited current flow between the active regions, and thus promotes desired device operation.Type: GrantFiled: March 8, 2007Date of Patent: June 29, 2010Assignee: Texas Instruments IncorporatedInventors: Xiaoju Wu, Fan-Chi Frank Hou, Pinghai Hao
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Patent number: 7687856Abstract: One embodiment of the present invention relates to a method for transistor matching. In this method, a channel is formed within a first transistor by applying a gate-source bias having a first polarity to the first transistor. The magnitude of a potential barrier in a pocket implant region of the first transistor is reduced by applying a body-source bias having the first polarity to the first transistor. Current flow is facilitated across the channel by applying a drain-source bias having the first polarity to the first transistor. Other methods and circuits are also disclosed.Type: GrantFiled: May 10, 2007Date of Patent: March 30, 2010Assignee: Texas Instruments IncorporatedInventors: Henry Litzmann Edwards, Tathagata Chatterjee, Mohamed Kamel Mahmoud, Xiaoju Wu
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Patent number: 7598547Abstract: We disclose the structure of a JFET device, the method of making the device and the operation of the device. The device is built near the top of a substrate. It has a buried layer that is electrically communicable to a drain terminal. It has a channel region over the buried layer contacting gate regions that connect to a gate terminal. The channel region, of which the length spans the distance between the buried layer and a source region, is connected to a source terminal. The device current flows in the channel substantially perpendicularly to the top surface of the substrate.Type: GrantFiled: December 12, 2006Date of Patent: October 6, 2009Assignee: Texas Instruments IncorporatedInventors: Sameer P Pendharker, Pinghai Hao, Xiaoju Wu
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Publication number: 20090153174Abstract: A test structure which can be used to detect residual conductive material such as polysilicon which can result from an under etch comprises a PMOS transistor and an OTP EPROM floating gate device. By testing the devices using different testing parameters, it can be determined whether residual conductive material remains subsequent to an etch, and where the residual conductive material is located on the device. A method for testing a semiconductor device using the test structure is also described.Type: ApplicationFiled: December 12, 2007Publication date: June 18, 2009Inventors: Xiaoju Wu, Jozef Czeslaw Mitros
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Patent number: 7457173Abstract: An electrically erasable programmable read only memory (EEPROM) (500) is disclosed having improved data retention and read/write endurance. The EEPROM also lacks a more conventional cross coupling arrangement and thus is more area efficient than conventional EEPROM cells. The EEPROM (500) includes a PMOS transistor portion (514a) and an NMOS transistor portion (514b), where respective currents of these devices are compared to one another (e.g., subtracted) to give a differential reading that provides for the state of the EEPROM (500).Type: GrantFiled: May 18, 2005Date of Patent: November 25, 2008Assignee: Texas Instruments IncorporatedInventor: Xiaoju Wu
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Publication number: 20080283966Abstract: Capacitor area is increased in the vertical direction by forming capacitors on topographic features on the chip. The features are formed during existing process steps. Adding vertical topography increases capacitance per unit area, reducing die size at no added development cost or mask steps.Type: ApplicationFiled: August 1, 2008Publication date: November 20, 2008Applicant: Texas Instruments IncorporatedInventors: Shanjen Pan, Xiaoju Wu, Peter Ying
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Publication number: 20080277731Abstract: One embodiment of the present invention relates to a method for transistor matching. In this method, a channel is formed within a first transistor by applying a gate-source bias having a first polarity to the first transistor. The magnitude of a potential barrier in a pocket implant region of the first transistor is reduced by applying a body-source bias having the first polarity to the first transistor. Current flow is facilitated across the channel by applying a drain-source bias having the first polarity to the first transistor. Other methods and circuits are also disclosed.Type: ApplicationFiled: May 10, 2007Publication date: November 13, 2008Inventors: Henry Litzmann Edwards, Tathagata Chatterjee, Mohamed Kamel Mahmoud, Xiaoju Wu
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Publication number: 20080225593Abstract: A single-poly EEPROM memory device comprises source and drain regions in a semiconductor body, a floating gate overlying a portion of the source and drain regions, which defines a source-to-floating gate capacitance and a drain-to-floating gate capacitance, wherein the source-to-floating gate capacitance is substantially greater than the drain-to-floating gate capacitance. The source-to-floating gate capacitance is, for example, at least about three times greater than the drain-to-floating gate capacitance to enable the memory device to be electrically programmed or erased by applying a potential between a source electrode and a drain electrode without using a control gate.Type: ApplicationFiled: March 12, 2007Publication date: September 18, 2008Inventors: Jozef Czeslaw Mitros, Xiaoju Wu
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Publication number: 20080217664Abstract: The disclosure herein pertains to fashioning a low noise junction field effect transistor (JFET) where transistor gate materials are utilized in forming and electrically isolating active areas of a the JFET. More particularly, active regions are self aligned with patterned gate electrode material and sidewall spacers which facilitate desirably locating the active regions in a semiconductor substrate. This mitigates the need for additional materials in the substrate to isolate the active regions from one another, where such additional materials can introduce noise into the JFET. This also allows a layer of gate dielectric material to remain over the surface of the substrate, where the layer of gate dielectric material provides a substantially uniform interface at the surface of the substrate that facilitates uninhibited current flow between the active regions, and thus promotes desired device operation.Type: ApplicationFiled: March 8, 2007Publication date: September 11, 2008Inventors: Xiaoju Wu, Fan-Chi Frank Hou, Pinghai Hao
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Patent number: 7402874Abstract: The formation of a one time programmable (OTP) transistor based electrically programmable read only memory (EPROM) cell (100) is disclosed. The cell (100) includes multiple concentric rings (108, 110) out of which gate structures are formed. An inner transistor based cell (130) formed from the inner ring (108) is shielded from isolation material (106) by one or more outer rings (110). The lack of overlap between the inner transistor and any isolation material promotes enhanced charge/data retention by mitigating high electric fields that may develop at such overlap regions (30, 32).Type: GrantFiled: April 29, 2005Date of Patent: July 22, 2008Assignee: Texas Instruments IncorporatedInventor: Xiaoju Wu
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Patent number: 7348228Abstract: A junction field effect transistor (JFET) is fashioned where a channel of transistor is buried deeply within the workpiece within which the JFET is formed. Burying the channel below the surface of the workpiece and/or away from overlying conductive materials distances a current that flows in the channel from outside influences, such as the effects of the overlying conductive materials. The deep channel also provides a more regular path for the current flowing therein by moving the channel away from non-uniformities on or near the surface of the workpiece, where said non-uniformities or irregularities would interrupt or otherwise disturb current flowing in a channel that is not as deep. These aspects of the deep channel serve to reduce noise and allow the transistor to operate in a more repeatable and predictable manner, among other things.Type: GrantFiled: May 25, 2006Date of Patent: March 25, 2008Assignee: Texas Instruments IncorporatedInventor: Xiaoju Wu
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Patent number: 7307309Abstract: A method forming a current path in a substrate (322) having a first conductivity type is disclosed. The method includes forming an impurity region (314) having a second conductivity type and extending from a face of the substrate to a first depth. A hole (305) is formed in the impurity region. A first dielectric layer (360-364) is formed on an inner surface of the hole. A first electrode (306) is formed in the hole adjacent the dielectric layer.Type: GrantFiled: March 4, 2004Date of Patent: December 11, 2007Assignee: Texas Instruments IncorporatedInventors: Pinghai Hao, Jozef Mitros, Xiaoju Wu