Patents by Inventor Jack H. Yuan
Jack H. Yuan 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: 7858472Abstract: An integrated non-volatile memory circuit is formed by first growing a thin dielectric layer on a semiconductor substrate surface, followed by depositing a layer of conductive material such as doped polysilicon on this dielectric layer, the conductive material then being separated into rows and columns of individual floating gates. Cell source and drain diffusions in the substrate are continuously elongated across the rows. Field dielectric deposited between the rows of floating gates provides electrical isolation between the rows. Shallow trenches may be included between rows without interrupting the conductivity of the diffusions along their lengths. A deep dielectric filled trench is formed in the substrate between the array and peripheral circuits as electrical isolation. Various techniques are included that increase the field coupling area between the floating gates and a control gate.Type: GrantFiled: March 22, 2007Date of Patent: December 28, 2010Assignee: SanDisk CorporationInventors: Jack H. Yuan, Eliyahou Harari, Yupin K. Fong, George Samachisa
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Patent number: 7834392Abstract: Non-volatile memory cells store a level of charge corresponding to the data being stored in a dielectric material storage element that is sandwiched between a control gate and the semiconductor substrate surface over channel regions of the memory cells. More than two memory states are provided by one of more than two levels of charge being stored in a common region of the dielectric material. More than one such common region may be included in each cell. In one form, two such regions are provided adjacent source and drain diffusions in a cell that also includes a select transistor positioned between them. In another form, NAND arrays of strings of memory cells store charge in regions of a dielectric layer sandwiched between word lines and the semiconductor substrate.Type: GrantFiled: July 27, 2009Date of Patent: November 16, 2010Assignee: SanDisk CorporationInventors: Eliyahou Harari, George Samachisa, Jack H. Yuan, Daniel C. Guterman
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Publication number: 20090286370Abstract: Non-volatile memory cells store a level of charge corresponding to the data being stored in a dielectric material storage element that is sandwiched between a control gate and the semiconductor substrate surface over channel regions of the memory cells. More than two memory states are provided by one of more than two levels of charge being stored in a common region of the dielectric material. More than one such common region may be included in each cell. In one form, two such regions are provided adjacent source and drain diffusions in a cell that also includes a select transistor positioned between them. In another form, NAND arrays of strings of memory cells store charge in regions of a dielectric layer sandwiched between word lines and the semiconductor substrate.Type: ApplicationFiled: July 27, 2009Publication date: November 19, 2009Inventors: Eliyahou Harari, George Samachisa, Jack H. Yuan, Daniel C. Guterman
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Patent number: 7615820Abstract: Self-aligned trench filling to isolate active regions in high-density integrated circuits is provided. A deep, narrow trench is etched into a substrate between active regions. The trench is filled by growing a suitable dielectric such as silicon dioxide. The oxide grows from the substrate to fill the trench and into the substrate to provide an oxide of greater width and depth than the trench. Storage elements for a NAND type flash memory system, for example, can be fabricated by etching the substrate to form the trench after or as part of etching to form NAND string active areas. This can ensure alignment of the NAND string active areas between isolation trenches. Because the dielectric growth process is self-limiting, an open area resulting from the etching process can be maintained between the active areas. A subsequently formed inter-gate dielectric layer and control gate layer can fill the open area to provide sidewall coupling between control gates and floating gates.Type: GrantFiled: May 13, 2008Date of Patent: November 10, 2009Assignee: SanDisk CorporationInventor: Jack H Yuan
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Patent number: 7579247Abstract: Non-volatile memory cells store a level of charge corresponding to the data being stored in a dielectric material storage element that is sandwiched between a control gate and the semiconductor substrate surface over channel regions of the memory cells. More than two memory states are provided by one of more than two levels of charge being stored in a common region of the dielectric material. More than one such common region may be included in each cell. In one form, two such regions are provided adjacent source and drain diffusions in a cell that also includes a select transistor positioned between them. In another form, NAND arrays of strings of memory cells store charge in regions of a dielectric layer sandwiched between word lines and the semiconductor substrate.Type: GrantFiled: January 25, 2008Date of Patent: August 25, 2009Assignee: SanDisk CorporationInventors: Eliyahou Harari, George Samachisa, Jack H. Yuan, Daniel C. Guterman
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Patent number: 7541237Abstract: Rows of memory cells are electrically isolated from one another by trenches formed in the substrate between the rows that are filled with a dielectric, commonly called “shallow trench isolation” or “STI.” Discontinuous source and drain regions of the cells are connected together by column oriented bit lines, preferably made of doped polysilicon, that extend in the column direction on top of the substrate. This structure is implemented in a flash memory array of cells having either one floating gate per cell or at least two floating gates per cell. A process of making a dual-floating gate memory cell array includes etching the word lines twice along their lengths, once to form openings through which source and drain implants are made and in which the conductive bit lines are formed, and second to form individual floating gates with a select transistor gate positioned between them that also serves to erase charge from the adjacent floating gates.Type: GrantFiled: October 4, 2007Date of Patent: June 2, 2009Assignee: Sandisk CorporationInventors: Jack H. Yuan, Jacob Haskell
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Patent number: 7517756Abstract: Floating gate structures are disclosed which have a base field coupled with the substrate and a narrow projection extending from the base away from the substrate. In one form, surfaces of a relatively large projection provide an increased surface area for a control gate that wraps around it, thereby increasing the coupling between the two. In another form, an erase gate wraps around a relatively small projection in order to take advantage of sharp edges of the projection to promote tunneling of electrons from the floating to the erase gate. In each case, the control or floating gate is positioned within the area of the floating gate in one direction, thereby not requiring additional substrate area for such memory cells.Type: GrantFiled: January 29, 2007Date of Patent: April 14, 2009Assignee: SanDisk CorporationInventor: Jack H. Yuan
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Patent number: 7491999Abstract: Several embodiments of flash EEPROM split-channel cell arrays are described that position the channels of cell select transistors along sidewalls of trenches in the substrate, thereby reducing the cell area. Select transistor gates are formed as part of the word lines and extend downward into the trenches with capacitive coupling between the trench sidewall channel portion and the select gate. In one embodiment, trenches are formed between every other floating gate along a row, the two trench sidewalls providing the select transistor channels for adjacent cells, and a common source/drain diffusion is positioned at the bottom of the trench. A third gate provides either erase or steering capabilities. In another embodiment, trenches are formed between every floating gate along a row, a source/drain diffusion extending along the bottom of the trench and upwards along one side with the opposite side of the trench being the select transistor channel for a cell.Type: GrantFiled: June 8, 2006Date of Patent: February 17, 2009Assignee: Sandisk CorporationInventors: Eliyahou Harari, Jack H. Yuan, George Samachisa, Henry Chien
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Patent number: 7479677Abstract: Non-volatile memory cells store a level of charge corresponding to the data being stored in a dielectric material storage element that is sandwiched between a control gate and the semiconductor substrate surface over channel regions of the memory cells. More than two memory states are provided by one of more than two levels of charge being stored in a common region of the dielectric material. More than one such common region may be included in each cell. In one form, two such regions are provided adjacent source and drain diffusions in a cell that also includes a select transistor positioned between them. In another form, NAND arrays of strings of memory cells store charge in regions of a dielectric layer sandwiched between word lines and the semiconductor substrate.Type: GrantFiled: January 25, 2008Date of Patent: January 20, 2009Assignee: Sandisk CorporationInventors: Eliyahou Harari, George Samachisa, Jack H. Yuan, Daniel C. Guterman
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Publication number: 20080211007Abstract: Self-aligned trench filling to isolate active regions in high-density integrated circuits is provided. A deep, narrow trench is etched into a substrate between active regions. The trench is filled by growing a suitable dielectric such as silicon dioxide. The oxide grows from the substrate to fill the trench and into the substrate to provide an oxide of greater width and depth than the trench. Storage elements for a NAND type flash memory system, for example, can be fabricated by etching the substrate to form the trench after or as part of etching to form NAND string active areas. This can ensure alignment of the NAND string active areas between isolation trenches. Because the dielectric growth process is self-limiting, an open area resulting from the etching process can be maintained between the active areas. A subsequently formed inter-gate dielectric layer and control gate layer can fill the open area to provide sidewall coupling between control gates and floating gates.Type: ApplicationFiled: May 13, 2008Publication date: September 4, 2008Inventor: Jack H. Yuan
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Patent number: 7416956Abstract: Self-aligned trench filling is used to isolate devices in high-density integrated circuits. A deep, narrow trench isolation region is formed in a substrate between devices. The trench region includes two trench portions. A first trench portion, located above a second trench portion, is filled with a deposited dielectric. The second trench portion is filled with a grown dielectric. Filling the lower trench portion by growing a dielectric material provides for an even distribution of dielectric material within the lower portion. Filling the upper trench portion by depositing a dielectric material provides for an even distribution of material in the upper portion while also protecting against encroachment of the dielectric into device channel regions, for example. Devices can be fabricated by etching the substrate to form the trench region after or as part of etching one or more layers formed above the substrate for the device.Type: GrantFiled: October 14, 2005Date of Patent: August 26, 2008Assignee: SanDisk CorporationInventor: Jack H. Yuan
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Patent number: 7402886Abstract: Self-aligned trench filling is used to isolate devices in high-density integrated circuits. A deep, narrow trench isolation region is formed in a substrate between devices. The trench region includes two trench portions. A first trench portion, located above a second trench portion, is filled with a deposited dielectric. The second trench portion is filled with a grown dielectric. Filling the lower trench portion by growing a dielectric material provides for an even distribution of dielectric material within the lower portion. Filling the upper trench portion by depositing a dielectric material provides for an even distribution of material in the upper portion while also protecting against encroachment of the dielectric into device channel regions, for example. Devices can be fabricated by etching the substrate to form the trench region after or as part of etching one or more layers formed above the substrate for the device.Type: GrantFiled: October 14, 2005Date of Patent: July 22, 2008Assignee: SanDisk CorporationInventor: Jack H. Yuan
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Publication number: 20080160680Abstract: Shield plates for reduced coupling between charge storage regions in nonvolatile semiconductor memory devices, and associated techniques for forming the same, are provided. Electrical fields associated with charge stored in the floating gates or other charge storage regions of a memory device can couple to neighboring charge storage regions because of the close, and continually decreasing proximity of these regions. A shield plate can be formed adjacent to the bit line sides of floating gates that face opposing bit line sides of adjacent floating gates. Insulating layers can be formed between each shield plate and its corresponding adjacent charge storage region. The insulating layers can extend to the levels of the upper surfaces of the control gates formed above the charge storage regions. In such a configuration, sidewall fabrication techniques can be implemented to form the insulating members and shield plates.Type: ApplicationFiled: December 28, 2006Publication date: July 3, 2008Inventor: Jack H. Yuan
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Publication number: 20080157169Abstract: Shield plates for reduced coupling between charge storage regions in nonvolatile semiconductor memory devices, and associated techniques for forming the same, are provided. Electrical fields associated with charge stored in the floating gates or other charge storage regions of a memory device can couple to neighboring charge storage regions because of the close, and continually decreasing proximity of these regions. A shield plate can be formed adjacent to the bit line sides of floating gates that face opposing bit line sides of adjacent floating gates. Insulating layers can be formed between each shield plate and its corresponding adjacent charge storage region. The insulating layers can extend to the levels of the upper surfaces of the control gates formed above the charge storage regions. In such a configuration, sidewall fabrication techniques can be implemented to form the insulating members and shield plates.Type: ApplicationFiled: December 28, 2006Publication date: July 3, 2008Inventor: Jack H. Yuan
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Patent number: 7381615Abstract: Methods for self-aligned trench filling to isolate active regions in high-density integrated circuits are provided. A deep, narrow trench is etched into a substrate between active regions. The trench is filled by growing a suitable dielectric such as silicon dioxide. The oxide grows from the substrate to fill the trench and into the substrate to provide an oxide of greater width and depth than the trench. A conductive layer used for the charge storage region of memory cells can be formed prior to formation of the trench isolation region. The trench can be etched after or as part of etching to form the individual charge storage regions. This can ensure alignment of active areas between isolation trenches. Because the dielectric growth process is self-limiting, an open area resulting from the etching process can be maintained between the active areas.Type: GrantFiled: November 23, 2004Date of Patent: June 3, 2008Assignee: SanDisk CorporationInventor: Jack H. Yuan
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Patent number: 7341918Abstract: Non-volatile memory cells store a level of charge corresponding to the data being stored in a dielectric material storage element that is sandwiched between a control gate and the semiconductor substrate surface over channel regions of the memory cells. More than two memory states are provided by one of more than two levels of charge being stored in a common region of the dielectric material. More than one such common region may be included in each cell. In one form, two such regions are provided adjacent source and drain diffusions in a cell that also includes a select transistor positioned between them. In another form, NAND arrays of strings of memory cells store charge in regions of a dielectric layer sandwiched between word lines and the semiconductor substrate.Type: GrantFiled: March 7, 2005Date of Patent: March 11, 2008Assignee: SanDisk CorporationInventors: Eliyahou Harari, George Samachisa, Jack H. Yuan, Daniel C. Guterman
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Patent number: 7342279Abstract: Non-volatile memory cells store a level of charge corresponding to the data being stored in a dielectric material storage element that is sandwiched between a control gate and the semiconductor substrate surface over channel regions of the memory cells. More than two memory states are provided by one of more than two levels of charge being stored in a common region of the dielectric material. More than one such common region may be included in each cell. In one form, two such regions are provided adjacent source and drain diffusions in a cell that also includes a select transistor positioned between them. In another form, NAND arrays of strings of memory cells store charge in regions of a dielectric layer sandwiched between word lines and the semiconductor substrate.Type: GrantFiled: March 7, 2005Date of Patent: March 11, 2008Assignee: SanDisk CorporationInventors: Eliyahou Harari, George Samachisa, Jack H. Yuan, Daniel C. Guterman
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Patent number: 7288455Abstract: Rows of memory cells are electrically isolated from one another by trenches formed in the substrate between the rows that are filled with a dielectric, commonly called “shallow trench isolation” or “STI.” Discontinuous source and drain regions of the cells are connected together by column oriented bit lines, preferably made of doped polysilicon, that extend in the columm direction on top of the substrate. This structure is implemented in a flash memory array of cells having either one floating gate per cell or at least two floating gates per cell. A process of making a dual-floating gate memory cell array includes etching the word lines twice along their lengths, once to form openings through which source and drain implants are made and in which the conductive bit lines are formed, and second to form individual floating gates with a select transistor gate positioned between them that also serves to erase charge from the adjacent floating gates.Type: GrantFiled: September 14, 2005Date of Patent: October 30, 2007Assignee: SanDisk CorporationInventors: Jack H. Yuan, Jacob Haskell
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Patent number: 7211866Abstract: An integrated non-volatile memory circuit is formed by first growing a thin dielectric layer on a semiconductor substrate surface, followed by depositing a layer of conductive material such as doped polysilicon on this dielectric layer, the conductive material then being separated into rows and columns of individual floating gates. Cell source and drain diffusions in the substrate are continuously-elongated across the rows. Field dielectric deposited between the rows of floating gates provides electrical isolation between the rows. Shallow trenches may be included between rows without interrupting the conductivity of the diffusions along their lengths. A deep dielectric filled trench is formed in the substrate between the array and peripheral circuits as electrical isolation. Various techniques are included that increase the field coupling area between the floating gates and a control gate.Type: GrantFiled: April 20, 2005Date of Patent: May 1, 2007Assignee: Sandisk CorporationInventors: Jack H. Yuan, Eliyahou Harari, Yupin K. Fong, George Samachisa
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Patent number: 7170131Abstract: Floating gate structures are disclosed which have a base field coupled with the substrate and a narrow projection extending from the base away from the substrate. In one form, surfaces of a relatively large projection provide an increased surface area for a control gate that wraps around it, thereby increasing the coupling between the two. In another form, an erase gate wraps around a relatively small projection in order to take advantage of sharp edges of the projection to promote tunneling of electrons from the floating to the erase gate. In each case, the control or floating gate is positioned within the area of the floating gate in one direction, thereby not requiring additional substrate area for such memory cells.Type: GrantFiled: May 18, 2005Date of Patent: January 30, 2007Assignee: SanDisk CorporationInventor: Jack H. Yuan