Abstract: A monolithic, three dimensional NAND string includes a first memory cell located over a second memory cell, a select transistor, a first word line of the first memory cell, a second word line of the second memory cell, a bit line, a source line, and a select gate line of the select transistor. The first and the second word lines are not parallel to the bit line, and the first and the second word lines extend parallel to at least one of the source line and the select gate line.
Abstract: The present invention provides systems, apparatus, and methods for forming three dimensional memory arrays using a multi-depth imprint lithography mask and a double subtractive process. An imprint lithography mask for manufacturing a memory layer in a three dimensional memory is described. The mask includes a translucent material formed with features for making an imprint in a transfer material to be used in a double subtractive process, the mask having a plurality of imprint depths. At least one imprint depth corresponds to rails for forming memory lines and at least one depth corresponds to pillars for forming memory cells. Numerous other aspects are disclosed.
Abstract: Methods, apparatus, and systems for memories that include a data array and a configuration array adapted to store configuration information for configuring the data array, are disclosed. The data array and the configuration array include a plurality of wordlines and a plurality of bitlines. The plurality of wordlines in the data array extend in the same direction as the plurality of wordlines in the configuration array. Likewise, the plurality of bitlines in the data array extend in the same direction as the plurality of bitlines in the configuration array. The configuration array may include a wordline driver layout, a bitline driver layout, relative positions of zia contact regions, a diode sensing orientation, a sense amplifier layout, a voltage regulator layout, and a layout of conductors proximate to the array that are each substantially similar to corresponding elements of the data array. Numerous other aspects are disclosed.
Abstract: A bottom-gate thin film transistor having a silicide gate is described. This transistor is advantageously formed as SONOS-type nonvolatile memory cell, and methods are described to efficiently and robustly form a monolithic three dimensional memory array of such cells. The fabrication methods described avoid photolithography over topography and difficult stack etches of prior art monolithic three dimensional memory arrays of charge storage devices. The use of a silicide gate rather than a polysilicon gate allows increased capacitance across the gate oxide.
Abstract: A method of forming a memory cell involves forming a semiconductor junction diode in series with an antifuse. The cell is programmed by rupture of the antifuse. The semiconductor junction diode comprises silicon, the silicon crystallized in contact with a silicide. The silicide apparently provides a template for crystallization, improving crystallinity and conductivity of the diode, and reducing the programming voltage required to program the cell. It is advantageous to reduce a dielectric layer (such as an oxide, nitride, or oxynitride) intervening between the silicon and the silicon-forming metal during the step of forming the silicide.
Abstract: Oxides of both nickel and cobalt have lower resistivity than either nickel oxide or cobalt oxide. Nickel oxide and cobalt oxide can be reversibly switched between two or more stable resistivity states by application of suitable electrical pulses. It is expected that oxides including both nickel and cobalt, or (NixCoy)O, will switch between resistivity states at lower voltage and/or current than will nickel oxide or cobalt oxide. A layer of (NixCoy)O can be paired with a diode or transistor to form a nonvolatile memory cell.
Abstract: In embodiments of the invention, a method of forming a monolithic three-dimensional memory array is provided, the method including forming a first memory level that includes a plurality of memory cells, each memory cell comprising a plurality of conductors comprising aluminum or copper, and forming a silicon diode in each memory cell, wherein the silicon diode is formed at temperatures compatible with the conductors. The silicon diode may be formed using a hot wire chemical vapor deposition technique, for example. Other aspects are also described.
Abstract: A plurality of integrated circuit features are provided in the context of an array of memory cells including a plurality of word lines and a plurality of bit lines. Each memory cell includes a floating body or is volatile memory. The aforementioned features may include, among others, an option whereby the foregoing bit lines may be situated below a channel region of corresponding memory cells, etc.
Abstract: A nonvolatile memory cell includes a steering element located in series with a storage element. The storage element includes a carbon material and the memory cell includes a rewritable cell having multiple memory levels.
Type:
Grant
Filed:
May 27, 2008
Date of Patent:
November 9, 2010
Assignee:
SanDisk 3D LLC
Inventors:
Xiying Chen, Bing K. Yen, Dat Nguyen, Huiwen Xu, George Samachisa, Tanmay Kumar, Er-Xuan Ping
Abstract: A nonvolatile memory device includes at least one memory cell which comprises a diode and a metal oxide antifuse dielectric layer, and a first electrode and a second electrode electrically contacting the at least one memory cell. In use, the diode acts as a read/write element of the memory cell by switching from a first resistivity state to a second resistivity state different from the first resistivity state in response to an applied bias.
Abstract: A first memory level includes a first plurality of memory cells that includes every memory cell in the first memory level. Each memory cell includes a vertically oriented p-i-n diode in the form of a pillar that includes a bottom heavily doped p-type region, a middle intrinsic or lightly doped region, and a top heavily doped n-type region. The first plurality of memory cells includes programmed cells and unprogrammed cells, wherein programmed cells comprise at least half of the first plurality of memory cells. Current flowing through the p-i-n diodes of at least 99 percent of the programmed cells when a voltage between about 1.5 volts and about 3.0 volts is applied between the bottom heavily doped p-type region and the top heavily doped n-type region is at least 1.5 microamps.
Abstract: A memory cell is described, the memory cell comprising a dielectric rupture antifuse and a layer of a resistivity-switching material arranged electrically in series, wherein the resistivity-switching material is a metal oxide or nitride compound, the compound including exactly one metal. The dielectric rupture antifuse is ruptured in a preconditioning step, forming a rupture region through the antifuse. The rupture region provides a narrow conductive path, serving to limit current to the resistivity-switching material, and improving control when the resistivity-switching layer is switched between higher- and lower-resistivity states.
Abstract: In some aspects, a method of forming a memory cell is provided that includes (1) forming a first conductor above a substrate; (2) forming a reversible resistance-switching element above the first conductor using a selective growth process; (3) forming a diode above the first conductor; and (4) forming a second conductor above the diode and the reversible resistance-switching element. Numerous other aspects are provided.
Type:
Grant
Filed:
June 29, 2007
Date of Patent:
November 2, 2010
Assignee:
SanDisk 3D LLC
Inventors:
April Schricker, Brad Herner, Mark Clark
Abstract: There is provided a monolithic three dimensional array of charge storage devices which includes a plurality of device levels, wherein at least one surface between two successive device levels is planarized by chemical mechanical polishing.
Type:
Grant
Filed:
January 23, 2009
Date of Patent:
November 2, 2010
Assignee:
SanDisk 3D LLC
Inventors:
Thomas H. Lee, Vivek Subramanian, James M. Cleeves, Mark G. Johnson, Paul M. Farmwald, Igor G. Kouznetsov
Abstract: A very high density field programmable memory is disclosed. An array is formed vertically above a substrate using several layers, each layer of which includes vertically fabricated memory cells. The cell in an N level array may be formed with N+1 masking steps plus masking steps needed for contacts. Maximum use of self alignment techniques minimizes photolithographic limitations. In one embodiment the peripheral circuits are formed in a silicon substrate and an N level array is fabricated above the substrate.
Abstract: A layer of resistivity-switching metal oxide or nitride can attain at least two stable resistivity states. Such a layer may be used in a state-change element in a nonvolatile memory cell, storing its data state, for example a “0” or a “1”, in this resistivity state. Including additional metal atoms in a layer of such a resistivity-switching metal oxide or nitride compound decreases the current required to cause switching between resistivity states, reducing power requirements for an array of memory cells storing data in the resistivity state of such a layer. In various embodiments a memory cell may include a layer of resistivity-switching metal oxide or nitride compound with added metal formed in series with another element, such as a diode or a transistor.
Abstract: A high density plasma oxidation process is provided in which a dielectric film is formed having a predetermined thickness. Plasma oxidation conditions are provided such that the growth rate of the dielectric film is limited in order to produce dielectric layer having a precise thickness and uniformity. The high density plasma oxidation process can be used to fabricate gate oxide layers, passivation layers and antifuse layers in semiconductor devices such as semiconductor memory devices and multi-level memory arrays.
Type:
Grant
Filed:
July 30, 2001
Date of Patent:
October 19, 2010
Assignee:
SanDisk 3D LLC
Inventors:
Michael A. Vyvoda, N. Johan Knall, James M. Cleeves
Abstract: A method of making a memory device includes forming a first conductive electrode, forming an insulating structure over the first conductive electrode, forming a resistivity switching element on a sidewall of the insulating structure, forming a second conductive electrode over the resistivity switching element, and forming a steering element in series with the resistivity switching element between the first conductive electrode and the second conductive electrode, wherein a height of the resistivity switching element in a first direction from the first conductive electrode to the second conductive electrode is greater than a thickness of the resistivity switching element in second direction perpendicular to the first direction.
Abstract: In a novel nonvolatile memory cell formed above a substrate, a diode is paired with a reversible resistance-switching material, preferably a metal oxide or nitride such as, for example, NixOy, NbxOy, TixOy, HFxOy, AlxOy, MgxOy, CoxOy, CrxOy, VxOy, ZnxOy, ZrxOy, BxNy, and AlxNy. In preferred embodiments, the diode is formed as a vertical pillar disposed between conductors. Multiple memory levels can be stacked to form a monolithic three dimensional memory array. In some embodiments, the diode comprises germanium or a germanium alloy, which can be deposited and crystallized at relatively low temperatures, allowing use of aluminum or copper in the conductors. The memory cell of the present invention can be used as a rewriteable memory cell or a one-time-programmable memory cell, and can store two or more data states.
Type:
Grant
Filed:
March 31, 2006
Date of Patent:
October 12, 2010
Assignee:
SanDisk 3D LLC
Inventors:
S. Brad Herner, Tanmay Kumar, Christopher J. Petti
Abstract: A method is described for isotropic or nearly isotropic shallow doping of a non-planar surface exposed in a void. The results of ion implantation, a common doping method, are inherently planar. Some fabrication methods and devices may require doping a surface of a non-planar feature exposed in a void, such as a trench. The feature is doped by flowing a gas which will provide the dopant over the exposed surfaces, or by exposing the surfaces to a plasma including the dopant. The feature may be a patterned feature, including a top surface and a sidewall. In a preferred embodiment, a semiconductor feature having a top surface and a sidewall is exposed in a trench formed in a dielectric, and a gas providing a p-type or n-type dopant is flowed in the trench, providing a p-type or n-type dopant to the semiconductor.