Abstract: A chopping technique, and associated structure, is implemented to cancel the magnetic 1/f noise contribution in a Tunneling Magnetoresistance (TMR) field sensor. The TMR field sensor comprises a first bridge circuit including multiple TMR elements to sense a magnetic field and a second circuit to apply a bipolar current pulse adjacent to each TMR element. The current lines are serially or sequentially connected to a current source to receive the bipolar current pulse. The field sensor has an output comprising a high output and a low output in response to the bipolar pulse. This asymmetric response allows a chopping technique for 1/f noise reduction in the field sensor.

Abstract: In forming a top electrode for a magnetoresistive device, photoresist used in patterning the electrode is stripped using a non-reactive stripping process. Such a non-reactive stripping process uses water vapor or some other non-oxidizing gas that also passivates exposed portions the magnetoresistive device. In such magnetoresistive devices, a non-reactive spacer layer is included that helps prevent diffusion between layers in the magnetoresistive device, where the non-reactive nature of the spacer layer prevents sidewall roughness that can interfere with accurate formation of the lower portions of the magnetoresistive device.

Abstract: Circuitry and methods provide an increased tunnel barrier endurance (lifetime) previously shortened by dielectric breakdown by providing a charging pulses of opposite polarity in comparison with write pulses. The charging pulse of opposite polarity may comprise equal or different width and amplitude than that of the write pulse, may be applied with each write pulse or a series of write pulses, and may be applied prior to or subsequent to the write pulse. A register is also used to keep track of the read pulse polarity such that read pulses of alternating polarity can be used in reading operations.

Abstract: A method and apparatus eliminate magnetic domain walls in a flux guide by applying, either simultaneously or sequentially, a current pulse along serially positioned reset lines to create a magnetic field along the flux guide, thereby removing the magnetic domain walls. By applying the current pulses in parallel and stepping through pairs of shorter reset lines segments via switches, less voltage is required.

Abstract: A boosted supply voltage generator is selectively activated and deactivated to allow operations that are sensitive to variations on the boosted voltage to be performed with a stable boosted voltage. Techniques for deactivating and reactivating the voltage generator are also disclosed that enable more rapid recovery from deactivation such that subsequent operations can be commenced sooner. Such techniques include storing state information corresponding to the voltage generator when deactivated, where the stored state information is used when reactivating the voltage generator. Stored state information can include a state of a clock signal provided to the voltage generator.

Abstract: A magnetoresistive memory device that stores data in the reference portion of spin-torque memory cells provides for more robust data storage. In normal operation, the memory cells use the free portion of the memory cell for data storage. Techniques for storing data in the reference portions of memory cells are presented, along with techniques for recovering data stored in the reference portions of memory cells.

Abstract: In some examples, a memory device generates and exposes parity/difference information to a test system to reduce overall test time. The parity/difference information may be generated based on parity bits read from the memory device and parity bits produced from data bits stored in the memory device. In some cases, the parity/difference information may be compared to an expected parity/difference to determine a number of correctable errors which occurred during testing, while the data bits may be compared to expected data to determine a number of uncorrectable errors which occurred during testing.

Abstract: A technique for detecting tampering attempts directed at a memory device includes setting each of a plurality of detection memory cells to an initial predetermined state, where corresponding portions of the plurality of detection memory cells are included in each of the arrays of data storage memory cells on the memory device. A plurality of corresponding reference bits on the memory device permanently store information representative of the initial predetermined state of each of the detection memory elements. When a tamper detection check is performed, a comparison between the reference bits and the current state of the detection memory cells is used to determine whether any of the detection memory cells have changed state from their initial predetermined states. Based on the comparison, a tamper detect indication is flagged if a threshold level of change is determined.

Abstract: A semiconductor package including a lead frame having a die pad and a plurality of leads arranged along at least a portion of a periphery of the semiconductor package, a semiconductor die secured to the die pad, wherein at least a portion of the semiconductor die extends beyond a periphery of the die pad, and a molding material encapsulating the semiconductor die and at least a portion of the die pad.

Abstract: A magnetoresistive memory element (for example, a spin-torque magnetoresistive memory element), includes first and second dielectric layers, wherein at least one of the dielectric layers is a magnetic tunnel junction. The memory element also includes a free magnetic layer having a first surface in contact with the first dielectric layer and a second surface in contact with the second dielectric layer. The free magnetic layer, which is disposed between the first and second dielectric layers, includes (i) a first high-iron interface region located along the first surface of the free magnetic layer, wherein the first high-iron interface region has at least 50% iron by atomic composition, and (ii) a first layer of ferromagnetic material adjacent to the first high-iron interface region, the first high-iron interface region between the first layer of ferromagnetic material and the first surface of the free magnetic layer.

Abstract: A semiconductor process integrates three bridge circuits, each include magnetoresistive sensors coupled as a Wheatstone bridge on a single chip to sense a magnetic field in three orthogonal directions. The process includes various deposition and etch steps forming the magnetoresistive sensors and a plurality of flux guides on one of the three bridge circuits for transferring a “Z” axis magnetic field onto sensors orientated in the XY plane.

Abstract: A conductive via disposed beneath a magnetic device and aligned therewith. In certain embodiments, an electrode formed on the conductive via may be polished to eliminate step functions or seams originating at the conductive via from propagating up through the various deposited layers. This integration approach allows for improved scaling of the MRAM devices to, for example, a 45 nanometer node.

Abstract: In some examples, a memory device is configured to receive a precharge command and an activate command. The memory device performs a first series of events related to the precharge command in response to receiving the precharge command and a second series of events related to the activate command in response to receiving the activate command. The memory device delays the start of the second series of events until the first series of events completes.

Abstract: A memory device is configured to identify a set of bit cells to be changed from a first state to a second state. In some examples, the memory device may apply a first voltage to the set of bit cells to change a least a first portion of the set of bit cells to the second state. In some cases, the memory device may also identify a second portion of the bit cells that remained in the first state following the application of the first voltage. In these cases, the memory device may apply a second voltage having a greater magnitude, duration, or both to the second portion of the set of bit cells in order to set the second portion of bit cells to the second state.

Abstract: In some examples, a memory device is configured with non-volatile memory array(s) having one or more associated volatile memory arrays. The memory device may include a non-destructive write mode configured to prevent access to the non-volatile memory array(s) during an initiation or calibration sequence performed by the memory device or an electronic device associated with the memory device to calibrate read and write access timing associated with the memory device.

Abstract: A magnetoresistive structure having two dielectric layers, and method of manufacturing same, includes a free magnetic layer positioned between the two dielectric layers. The method of manufacture comprises at least two etch processes and at least an encapsulation process interposed therebetween wherein the encapsulation is formed on sidewalls of the partially formed magnetoresistive stack between etch processes.

Abstract: Memory cells in a spin-torque magnetic random access memory (MRAM) include at least two magnetic tunnel junctions within each memory cell, where each memory cell only stores a single data bit of information. Access circuitry coupled to the memory cells are able to read from and write to a memory cell even when one of the magnetic tunnel junctions within the memory cell is defective and is no longer functional. Self-referenced and referenced reads can be used in conjunction with the multiple magnetic tunnel junction memory cells. In some embodiments, writing to the memory cell forces all magnetic tunnel junctions into a known state, whereas in other embodiments, a subset of the magnetic tunnel junctions are forced to a known state.

Abstract: A cell bias control circuit maximizes the performance of devices in the read/write path of memory cells (magnetic tunnel junction device+transistor) without exceeding leakage current or reliability limits by automatically adjusting multiple control inputs of the read/write path at the memory array according to predefined profiles over supply voltage, temperature, and process corner variations by applying any specific reference parameter profiles to the memory array.

Abstract: Techniques and circuits for testing and configuring magnetic memory devices are presented. Registers and nonvolatile storage is included on the memory devices for storing values used to control testing of the memory devices as well as for configuring parameters related to both testing and normal operation. Examples include adjustment of bias voltages, sense amplifier offset values, and timing parameters to improve the efficiency of testing operations as well as improve reliability and speed of normal operation.

Abstract: A memory device includes memory arrays configured to store pages of data organized into multiple ECC words. The memory device also includes at least one input/output pad for each ECC word associated with a page, such that a first level of error correction may be performed by the memory device on each of the ECC words associated with a page and a second level of error correction is performed on the data output by each of the input/output pads during a particular period of time.