Abstract: A method of making a monolithic, three dimensional NAND string including a first memory cell located over a second memory cell, includes growing a semiconductor active region of second memory cell, and epitaxially growing a semiconductor active region of the first memory cell on the semiconductor active region of the second memory cell in a different growth step from the step of growing the semiconductor active region of second memory cell.

Abstract: Circuits and methods are described for decoding exemplary memory arrays of programmable and, in some embodiments, re-writable passive element memory cells, which are particularly useful for extremely dense three-dimensional memory arrays having more than one memory plane. In addition, circuits and methods are described for selecting one or more array blocks of such a memory array, for selecting one or more word lines and bit lines within selected array blocks, for conveying data information to and from selected memory cells within selected array blocks, and for conveying unselected bias conditions to unselected array blocks.

Abstract: The invention provides for polysilicon vias connecting conductive polysilicon layers formed at different heights. Polysilicon vias are advantageously used in a monolithic three dimensional memory array of charge storage transistors. Polysilicon vias according to the present invention can be used, for example, to connect the channel layer of a first device level of charge storage transistor memory cells to the channel layer of a second device layer of such cells formed above the first device level. Similarly, vias according to the present invention can be used to connect the wordline of a first device level of charge storage transistor memory cells to the channel layer of a second device layer of such cells.

Abstract: A nonvolatile memory cell according to the present invention comprises a bottom conductor, a semiconductor pillar, and a top conductor. The semiconductor pillar comprises a junction diode, including a bottom heavily doped region, a middle intrinsic or lightly doped region, and a top heavily doped region, wherein the conductivity types of the top and bottom heavily doped region are opposite. The junction diode is vertically oriented and is of reduced height, between about 500 angstroms and about 3500 angstroms. A monolithic three dimensional memory array of such cells can be formed comprising multiple memory levels, the levels monolithically formed above one another.

Abstract: An exemplary amplifier circuit includes a first group of spatially distributed final amplifier stages having a first configuration, and a second group of spatially distributed final amplifier stages having a second configuration different than the first configuration. Both groups share the same control node for their respective final amplifier stages, and both groups share the same amplifier output node. Each group is typically enabled at a time that the other is disabled. In certain embodiments incorporating a memory array, only one critical analog node must be routed throughout the memory array.

Abstract: Method and device for providing voltage generation with load-based control are disclosed. The voltage generation can be provided within an electronic device, such as a memory system that provides data storage. In one embodiment, an electrical load imposed on a generated voltage can be monitored and used to dynamically control strength of the generated voltage. For example, for greater electrical loads, the generated voltage can be provided with a greater strength, and for lesser electrical loads, the generated voltage can be provided with a lesser strength. By compensating the generated voltage for the nature of the imposed electrical load, the generated voltage can be provided in a stable manner across a significant range of loads. In the case of a memory system, stability in the generated voltage provides for reduced voltage ripple and thus improved sensing margins. The voltage generation is well suited for use in portable memory products (e.g., memory cards) to generate one or more internal voltages.

Abstract: An improved nonvolatile memory cell made by a method for fabricating a three dimensional monolithic memory with increased density. The memory cell includes at least a part of a first conductor, a semiconductor element, and at least a part of a second conductor. The method includes forming conductors preferably comprising tungsten, then filling and planarizing; above the conductors forming semiconductor elements, preferably comprising two diode portions, optionally forming an antifuse above or below both of the diode portions, and then filling and planarizing; and continuing to form conductors and semiconductor elements in multiple stories of memories. The arrangement of processing steps and the choice of materials decreases aspect ratio of each memory cell, improving the reliability of gap fill and preventing etch undercut.

Abstract: In formation of monolithic three dimensional memory arrays, a photomask may be used more than once. Reuse of a photomask creates second, third or more instances of reference marks used by the stepper to achieve alignment (alignment marks) and to measure alignment achieved (overlay marks) directly above prior instances of the same reference mark. The prior instances of the same reference mark may cause interference with the present instance of the reference mark, complicating alignment and measurement. Using the methods of the present invention, blocking structure is created vertically interposed between subsequent instances of the same reference mark, preventing interference.

Abstract: An exemplary amplifier circuit includes a first group of spatially distributed final amplifier stages having a first configuration, and a second group of spatially distributed final amplifier stages having a second configuration different than the first configuration. Both groups share the same control node for their respective final amplifier stages, and both groups share the same amplifier output node. Each group is typically enabled at a time that the other is disabled. In certain embodiments incorporating a memory array, only one critical analog node must be routed throughout the memory array.

Abstract: Circuits and methods are described for decoding exemplary memory arrays of programmable and, in some embodiments, re-writable passive element memory cells, which are particularly useful for extremely dense three-dimensional memory arrays having more thane one memory plane. In addition, circuits and methods are described for selecting one or more array blocks of such a memory array, for selecting one or more word lines and bit lines within selected array blocks, for conveying data information to and from selected memory cells within selected array blocks, and for conveying unselected bias conditions to unselected array blocks.

Abstract: A method is provided comprising reading a set of memory cells indicating whether stored redundancy information is reliable and, if the set of memory cells indicates that the stored redundancy information is reliable, determining whether to read primary memory or redundant memory based on the stored redundancy information. Another method is provided comprising reading a set of memory cells associated with a group of memory cells in a primary memory, the set of memory cells indicating whether data can be reliably stored in the group of memory cells; if the set of memory cells indicates that data can be reliably stored in the group of memory cells, storing data in the group of memory cells; and if the set of memory cells does not indicate that data can be reliably stored in the group of memory cells, storing data in a group of memory cells in a redundant memory. In another preferred embodiment, a method for providing memory redundancy is provided.

Abstract: Methods involve using a memory array having memory cells comprising a diode and an antifuse, in which the antifuse is made smaller and programmed at lower voltage by using an antifuse material having a higher dielectric constant and a higher acceleration factor than those of silicon dioxide, and in which the diode is made of a material having a lower band gap than that of silicon. Such memory arrays can be made to have long operating lifetimes by using the high acceleration factor and lower band gap materials. Antifuse materials having dielectric constants between 5 and 27, for example, hafnium silicon oxynitride or hafnium silicon oxide, are particularly effective. Diode materials with band gaps lower than that of silicon, such as germanium or a silicon-germanium alloy, are particularly effective.

Abstract: In a first preferred embodiment of the present invention, conductive features are formed on a first dielectric etch stop layer, and a second dielectric material is deposited over and between the conductive features. A via etch to the conductive features which is selective between the first and second dielectrics will stop on the dielectric etch stop layer, limiting overetch. In a second embodiment, a plurality of conductive features is formed in a subtractive pattern and etch process, filled with a dielectric fill, and then a surface formed coexposing the conductive features and dielectric fill. A dielectric etch stop layer is deposited on the surface, then a third dielectric covers the dielectric etch stop layer. When a contact is etched through the third dielectric, this selective etch stops on the dielectric etch stop layer. A second etch makes contact to the conductive features.

Abstract: A memory array having memory cells comprising a diode and an antifuse can be made smaller and programmed at lower voltage by using an antifuse material having a higher dielectric constant and a higher acceleration factor than those of silicon dioxide, and by using a diode having a lower band gap than that of silicon. Such memory arrays can be made to have long operating lifetimes by using the high acceleration factor and lower band gap materials. Antifuse materials having dielectric constants between 5 and 27, for example, hafnium silicon oxynitride or hafnium silicon oxide, are particularly effective. Diode materials with band gaps lower than that of silicon, such as germanium or a silicon-germanium alloy, are particularly effective.

Abstract: A four level passive element cell has memory states corresponding to decreasing resistance levels, which are preferably mapped respectively to data states 11, 01, 00, and 10 . The LSB and MSB are preferably mapped as part of different pages. To discriminate between memory cell states, the selected bit line current is sensed for at least two different combinations of reference current level and read bias voltage. A mid-level reference is used to read the LSB. When reading the MSB, a first reference between the 10 and 00 data states, and a second reference between 01 and 11 data states may be used, and the mid-level reference need not be used. In certain embodiments, the bit line current may be simultaneously compared against the first and second references, without requiring a delay to stabilize the bit line current to a different value, and the MSB generated accordingly.

Abstract: A reversible polarity decoder circuit is disclosed which is particularly suitable for implementing a multi-headed decoder structure, such as might be used for decoding word lines, and particularly in a 3D memory array. The decoder circuit provides an overdrive voltage bias to the gates of half-selected word line driver circuits to solidly maintain the half-selected word lines at an inactive level. If the memory array is biased at or near the breakdown voltage, this overdrive voltage may be greater than the breakdown voltage of the decoder transistors. However, in the embodiments described, the decoder circuit accomplishes this without impressing a voltage greater than the breakdown voltage across any of the decoder transistors, for either polarity of operation of the decoder circuit.

Abstract: A four level passive element cell has memory states corresponding to decreasing resistance levels, which are preferably mapped respectively to data states 11, 01, 00, and 10. The LSB and MSB are preferably mapped as part of different pages. To discriminate between memory cell states, the selected bit line current is sensed for at least two different combinations of reference current level and read bias voltage. A mid-level reference is used to read the LSB. When reading the MSB, a first reference between the 10 and 00 data states, and a second reference between 01 and 11 data states may be used, and the mid-level reference need not be used. In certain embodiments, the bit line current may be simultaneously compared against the first and second references, without requiring a delay to stabilize the bit line current to a different value, and the MSB generated accordingly.

Abstract: A method for annealing a diode formed of a silicon-germanium alloy that minimizes leakage current is disclosed. The method includes the steps of forming semiconductor pillars of an alloy of silicon and germanium; heating the pillars at a first temperature for at least 30 minutes, and then heating the pillars at a second temperature higher than the first temperature of the alloy for up to 120 seconds. The invention further includes a monolithic three dimensional memory array of a plurality of p-i-n diodes, the p-i-n diodes being formed of a silicon-germanium alloy that have been subjected to a two-stage heating process.

Abstract: A reversible polarity decoder circuit is disclosed which is particularly suitable for implementing a multi-headed decoder structure, such as might be used for decoding word lines, and particularly in a 3D memory array. The decoder circuit provides an overdrive voltage bias to the gates of half-selected word line driver circuits to solidly maintain the half-selected word lines at an inactive level. If the memory array is biased at or near the breakdown voltage, this overdrive voltage may be greater than the breakdown voltage of the decoder transistors. However, in the embodiments described, the decoder circuit accomplishes this without impressing a voltage greater than the breakdown voltage across any of the decoder transistors, for either polarity of operation of the decoder circuit.

Abstract: A passive element memory device is provided that includes memory cells comprised of a state change element in series with a steering element. Controlled pulse operations are used to perform resistance changes associated with set and reset operations in an array of memory cells. Selected memory cells in an array are switched to a target resistance state in one embodiment by applying a positive voltage pulse to selected first array lines while applying a negative voltage pulse to selected second array lines. An amplitude of voltage pulses can be increased while being applied to efficiently and safely switch the resistance of cells having different operating characteristics. The cells are subjected to reverse biases in embodiments to lower leakage currents and increase bandwidth. The amplitude and duration of voltage pulses are controlled, along with the current applied to selected memory cells in some embodiments.