Abstract: Apparatus and associated method for asymmetric write current compensation for resistive sense memory (RSM) cells, such as but not limited to spin-torque transfer random access memory (STRAM) or resistive random access memory (RRAM) cells. In accordance with some embodiments, an RSM cell includes an RSM element coupled to a switching device. The switching device has a plurality of terminals. A control circuit compensates for asymmetric write characteristics of the RSM cell by limiting a range of voltage differentials across the terminals so as to be equal to or less than a magnitude of a source voltage applied to the switching device, thereby providing bi-directional write currents of substantially equal magnitude through the RSM element.

Abstract: A method and apparatus for reading data from a non-volatile memory cell. In some embodiments, a cross-point array of non-volatile memory cells is arranged into rows and columns. A selection circuit is provided that is capable of activating the first block of memory cells while deactivating the second block of memory cells. Further, a read circuit is provided that is capable of reading a logical state of a predetermined memory cell in the first block of memory cells with a reduced leak current by programming a first resistive state to the block selection elements corresponding to the first block of memory cells while programming a second resistive state to the block selection elements corresponding to the second block of memory cells.

Abstract: A memory unit including a first transistor spanning a first transistor region in a first layer of the memory unit; a second transistor spanning a second transistor region in a second layer of the memory unit; a first resistive sense memory (RSM) cell spanning a first memory region in a third layer of the memory unit; and a second RSM cell spanning a second memory region in the third layer of the memory unit, wherein the first transistor is electrically coupled to the first RSM cell, and the second transistor is electrically coupled to the second RSM cell, wherein the second layer is between the first and third layers, wherein the first and second transistor have an transistor overlap region, and wherein the first memory region and the second memory region do not extend beyond the first transistor region and the second transistor region.

Abstract: A spin-transfer torque memory apparatus and self-reference read schemes are described. One method of self-reference reading a spin-transfer torque memory unit includes applying a first read current through a magnetic tunnel junction data cell and forming a first bit line read voltage, the magnetic tunnel junction data cell having a first resistance state and storing the first bit line read voltage in a first voltage storage device. Then applying a low resistance state polarized write current through the magnetic tunnel junction data cell, forming a low second resistance state magnetic tunnel junction data cell. A second read current is applied through the low second resistance state magnetic tunnel junction data cell to forming a second bit line read voltage. The second bit line read voltage is stored in a second voltage storage device.

Abstract: A spin-transfer torque memory apparatus and non-destructive self-reference read schemes are described. One method of self-reference reading a spin-transfer torque memory unit includes applying a first read current through a magnetic tunnel junction data cell and forming a first bit line read voltage and storing the first bit line read voltage in a first voltage storage device. The magnetic tunnel junction data cell has a first resistance state. Then the method includes applying a second read current thorough the magnetic tunnel junction data cell having the first resistance state and forming a second bit line read voltage and storing the second bit line read voltage in a second voltage storage device. The first read current is less than the second read current. Then the stored first bit line read voltage is compared with the stored second bit line read voltage to determine whether the first resistance state of the magnetic tunnel junction data cell was a high resistance state or low resistance state.

Abstract: Various embodiments of the present invention are generally directed to a method and apparatus for providing different bit set modes for a resistive sense memory (RSM) array, such as a spin-torque transfer random access memory (STRAM) or resistive random access memory (RRAM) array. In accordance with some embodiments, a group of RSM cells in a non-volatile semiconductor memory array is identified for application of a bit set operation. A bit set value is selected from a plurality of bit set values each separately writable to the RSM cells to place said cells in a selected resistive state. The selected bit set value is thereafter written to at least a portion of the RSM cells in the identified group.

Abstract: A magnetic memory device includes a magnetic tunnel junction having a free magnetic layer having a magnetization orientation that is switchable between a high resistance state magnetization orientation and a low resistance state magnetization orientation and a memristor solid state element electrically coupled to the magnetic tunnel junction. The memristor has a device response that is an integrated voltage versus an integrated current.

Abstract: A memory array includes a plurality of magnetic tunnel junction cells arranged in a 2 by 2 array. Each magnetic tunnel junction cell is electrically coupled between a bit line and a source line and each magnetic tunnel junction cell electrically coupled to a transistor. Each magnetic tunnel junction cell is configured to switch between a high resistance state and a low resistance state by passing a write current passing though the magnetic tunnel junction cell. A first word line is electrically coupled to a gate of first set of two of the transistors and a second word line is electrically coupled to a gate of a second set of two of the transistors. The source line is a common source line for the plurality of magnetic tunnel junctions.

Abstract: A method and apparatus for reading data from a non-volatile memory cell. In some embodiments, a cross-point array of non-volatile memory cells is arranged into rows and columns. A selection circuit is provided that is capable of activating the first block of memory cells while deactivating the second block of memory cells. Further, a read circuit is provided that is capable of reading a logical state of a predetermined memory cell in the first block of memory cells with a reduced leak current by programming a first resistive state to the block selection elements corresponding to the first block of memory cells while programming a second resistive state to the block selection elements corresponding to the second block of memory cells.

Abstract: The present disclosure relates to memory arrays with read reference voltage cells. In particular the present disclosure relates to variable resistive memory cell apparatus and arrays that include a high resistance state reference memory cell and a low resistance state reference memory cell that provides a reliable average reference voltage on chip to compare to a read voltage of a selected memory cell and determine if the selected memory cell is in the high resistance state or low resistance state. These memory arrays are particularly suitable for use with spin-transfer torque memory cells and resolves many systematic issues related to generation of a reliable reference voltage.

Abstract: Variable resistive punchthrough access methods are described. The methods include switching a variable resistive data cell from a high resistance state to a low resistance state by passing a write current through the magnetic tunnel junction data cell in a first direction. The write current is provided by a transistor being electrically coupled to the variable resistive data cell and a source line. The write current passes through the transistor in punchthrough mode.

Abstract: Method and apparatus for operating a memory device with a status register. In some embodiments, the memory device has a plurality of individually programmable non-volatile memory cells comprised of at least a resistive sense memory. The memory device engages an interface and maintains a status register in some embodiments by logging at least an error or busy signal during data transfer operations.

Abstract: Apparatus and method for write current compensation in a non-volatile memory cell, such as but not limited to spin-torque transfer random access memory (STRAM) or resistive random access memory (RRAM). In accordance with some embodiments, a non-volatile memory cell has a resistive sense element (RSE) coupled to a switching device, the RSE having a hard programming direction and an easy programming direction opposite the hard programming direction. A voltage boosting circuit includes a capacitor which adds charge to a nominal non-zero voltage supplied by a voltage source to a node to generate a temporarily boosted voltage. The boosted voltage is applied to the switching device when the RSE is programmed in the hard programming direction.

Abstract: A method and apparatus for writing data to a non-volatile memory cell, such as an RRAM memory cell. In some embodiments, a semiconductor array of non-volatile memory cells comprises a resistive sense element (RSE) and a switching device. A RSE of a plurality of memory cells is connected to a bit line while the switching device of a plurality of memory cells is connected to a word line and operated to select a memory cell. A source line is connected to the switching device and connects a series of memory cells together. Further, a driver circuit is connected to the bit line and writes a selected RSE of a selected source line to a selected resistive state by passing a write current along a write current path that passes through the selected RSE and through at least a portion of the remaining RSE connected to the selected source line.

Abstract: Apparatus and associated method for asymmetric write current compensation for resistive sense memory (RSM) cells, such as but not limited to spin-torque transfer random access memory (STRAM) or resistive random access memory (RRAM) cells. In accordance with some embodiments, an RSM cell includes an RSM element coupled to a switching device. The switching device has a plurality of terminals. A control circuit compensates for asymmetric write characteristics of the RSM cell by limiting a range of voltage differentials across the terminals so as to be equal to or less than a magnitude of a source voltage applied to the switching device, thereby providing bi-directional write currents of substantially equal magnitude through the RSM element.

Abstract: A memory array includes a plurality of magnetic tunnel junction cells arranged in a 2 by 2 array. Each magnetic tunnel junction cell is electrically coupled between a bit line and a source line and each magnetic tunnel junction cell electrically coupled to a transistor. Each magnetic tunnel junction cell is configured to switch between a high resistance state and a low resistance state by passing a write current passing though the magnetic tunnel junction cell. A first word line is electrically coupled to a gate of first set of two of the transistors and a second word line is electrically coupled to a gate of a second set of two of the transistors. The source line is a common source line for the plurality of magnetic tunnel junctions.

Abstract: A magnetic memory device includes a magnetic tunnel junction having a free magnetic layer having a magnetization orientation that is switchable between a high resistance state magnetization orientation and a low resistance state magnetization orientation and a memristor solid state element electrically coupled to the magnetic tunnel junction. The memristor has a device response that is an integrated voltage versus an integrated current.

Abstract: Variable write and read methods for resistance random access memory (RRAM) are disclosed. The methods include initializing a write sequence and verifying the resistance state of the RRAM cell. If a write pulse is needed, then two or more write pulses are applied through the RRAM cell to write the desired data state to the RRAM cell. Each subsequent write pulse has substantially the same or greater write pulse duration. Subsequent write pulses are applied to the RRAM cell until the RRAM cell is in the desired data state or until a predetermined number of write pulses have been applied to the RRAM cell. A read method is also disclosed where subsequent read pulses are applied through the RRAM cell until the read is successful or until a predetermined number of read pulses have been applied to the RRAM cell.

Abstract: A memory unit including a first transistor spanning a first transistor region in a first layer of the memory unit; a second transistor spanning a second transistor region in a second layer of the memory unit; a first resistive sense memory (RSM) cell spanning a first memory region in a third layer of the memory unit; and a second RSM cell spanning a second memory region in the third layer of the memory unit, wherein the first transistor is electrically coupled to the first RSM cell, and the second transistor is electrically coupled to the second RSM cell, wherein the second layer is between the first and third layers, wherein the first and second transistor have an transistor overlap region, and wherein the first memory region and the second memory region do not extend beyond the first transistor region and the second transistor region.

Abstract: A method and apparatus for repairing a stuck-at defect condition in a non-volatile memory cell, such as a spin-torque transfer random access memory (STRAM). In some embodiments, a resistive sense element has a magnetic tunneling junction (MTJ) and a repair plane located adjacent to the resistive sense element. The repair plane injects a magnetic field in the MTJ to repair a stuck-at defect condition.