Abstract: Magnetic tunnel junction (MTJ) devices with varied breakdown voltages in different memory arrays fabricated in a same semiconductor die to facilitate different memory applications are disclosed. In exemplary aspects disclosed herein, MTJ devices are fabricated in a semiconductor die to provide at least two different memory arrays. MTJ devices in each memory array are fabricated to have different breakdown voltages. For example, it may be desired to fabricate a One-Time-Programmable (OTP) memory array in the semiconductor die using MTJ devices having a first, lower breakdown voltage, and a separate magneto-resistive random access memory (MRAM) in a same semiconductor die with MTJ devices having a higher breakdown voltage. Thus, in this example, lower breakdown voltage MTJ devices in OTP memory array require less voltage to program, while higher breakdown voltage MTJ devices in MRAM can maintain a desired write operation margin to avoid or reduce write operations causing dielectric breakdown.

Abstract: Dynamically controlling voltage for access operations to magneto-resistive random access memory (MRAM) bit cells to account for ambient temperature is disclosed. An MRAM bit cell process variation measurement circuit (PVMC) is configured to measure process variations and ambient temperature in magnetic tunnel junctions (MTJs) that affect MTJ resistance, which can change the write current at a given fixed supply voltage applied to an MRAM bit cell. These measured process variations and ambient temperature are used to dynamically control a supply voltage for access operations to the MRAM to reduce the likelihood of bit errors and reduce power consumption. The MRAM bit cell PVMC may also be configured to measure process variations and/or ambient temperatures in logic circuits that represent the process variations and ambient temperatures in access transistors employed in MRAM bit cells in the MRAM to determine variations in the switching speed (i.e., drive strength) of the access transistors.

Abstract: Multiple (multi-) level cell (MLC) non-volatile (NV) memory (NVM) matrix circuits for performing matrix computations with multi-bit input vectors are disclosed. An MLC NVM matrix circuit includes a plurality of NVM storage string circuits that each include a plurality of MLC NVM storage circuits each containing a plurality of NVM bit cell circuits each configured to store 1-bit memory state. Thus, each MLC NVM storage circuit stores a multi-bit memory state according to memory states of its respective NVM bit cell circuits. Each NVM bit cell circuit includes a transistor whose gate node is coupled to a word line among a plurality of word lines configured to receive an input vector. Activation of the gate node of a given NVM bit cell circuit in an MLC NVM storage circuit controls whether its resistance is contributed to total resistance of an MLC NVM storage circuit coupled to a respective source line.

Abstract: Voltage-switched magneto-resistive random access memory (MRAM) employing separate read operation circuit paths from a shared spin torque write operation circuit path is disclosed. The MRAM includes an MRAM array that includes MRAM bit cell rows each including a plurality of MRAM bit cells. MRAM bit cells on an MRAM bit cell row share a common electrode to provide a shared write operation circuit path for write operations. Dedicated read operation circuit paths are also provided for each MRAM bit cell separate from the write operation circuit path. As a result, the read operation circuit paths for the MRAM bit cells do not vary as a result of the different layout locations of the MRAM bit cells with respect to the common electrode. Thus, the read parasitic resistances of the MRAM bit cells do not vary from each other because of their different coupling locations to the common electrode.

Abstract: Magnetoresistive (MR) sensors employing dual MR devices for differential MR sensing are provided. These MR sensors may be used as biosensors to detect the presence of biological materials as an example. An MR sensor includes dual MR sensor devices that may be tunnel magnetoresistive (TMR) devices or giant magnetoresistive (GMR) devices as examples. The MR devices are arranged such that a channel is formed between the MR devices for receiving magnetic nanoparticles. A magnetic stray field generated by the magnetic nanoparticles causes free layers in the MR devices to rotate in opposite directions, thus causing differential resistances between the MR devices for greater sensing sensitivity. Further, as another aspect, by providing the channel between the MR devices, the magnetic stray field generated by the magnetic nanoparticles can more easily rotate the magnetic moment orientation of the free layers in the MR devices, thus further increasing sensitivity.

Abstract: Magnetic tunnel junction (MTJ) devices with a heterogeneous free layer structure particularly suited for efficient spin-torque-transfer (STT) magnetic random access memory (MRAM) (STT MRAM) are disclosed. In one aspect, a MTJ structure with a reduced thickness first pinned layer section provided below a first tunnel magneto-resistance (TMR) barrier layer is provided. The first pinned layer section includes one pinned layer magnetized in one magnetic orientation. In another aspect, a second pinned layer section and a second TMR barrier layer are provided above a free layer section and above the first TMR barrier layer in the MTJ. The second pinned layer is magnetized in a magnetic orientation that is anti-parallel (AP) to that of the first pinned layer section. In yet another aspect, the free layer comprises first and second heterogeneous layers separated by an anti-ferromagnetic coupling spacer, the first and second heterogeneous layers differing in their magnetic anisotropy.

Abstract: Certain aspects of the present disclosure generally relate to a semiconductor variable capacitor, and techniques for fabricating the same, implemented using a threshold voltage implant region. For example, the semiconductor variable capacitor generally includes a first non-insulative region disposed above a first semiconductor region, a second non-insulative region disposed above the first semiconductor region, and a threshold voltage (Vt) implant region interposed between the first non-insulative region and the first semiconductor region and disposed adjacent to the second non-insulative region. In certain aspects, the semiconductor variable capacitor also includes a control region disposed above the first semiconductor region such that a capacitance between the first non-insulative region and the second non-insulative region is configured to be adjusted by varying a control voltage applied to the control region.

Abstract: A method of fabrication of a device includes forming a first metallization layer that is coupled to a logic device of the device. The method further includes forming a second metallization layer that is coupled to a magnetoresistive random access memory (MRAM) module of the device. The second metallization layer is independent of the first metallization layer.

Abstract: Back gate biasing magneto-resistive random access memory (MRAM) bit cells to reduce or avoid write operation failures caused by source degeneration are disclosed. In one aspect, an MRAM bit cell includes a magnetic tunnel junction (MTJ) device and an access transistor used to control reading and writing of the MRAM bit cell. To reduce or avoid source degeneration caused by a voltage at a source region of the access transistor in response to a write operation, a back gate bias voltage is applied to a back gate electrode of the access transistor, the back gate bias voltage controlled to be greater than or equal to a back gate voltage associated with the access transistor having a nominal threshold voltage corresponding to operation without source degeneration plus a voltage corresponding to the source region of the access transistor.

Abstract: A material stack of a synthetic anti-ferromagnetic (SAF) reference layer of a perpendicular magnetic tunnel junction (MTJ) may include an SAF coupling layer. The material stack may also include and an amorphous spacer layer on the SAF coupling layer. The amorphous spacer layer may include an alloy or multilayer of tantalum and cobalt or tantalum and iron or cobalt and iron and tantalum. The amorphous spacer layer may also include a treated surface of the SAF coupling layer.

Abstract: Ferroelectric-modulated Schottky non-volatile memory is disclosed. A resistive memory element is provided that is based on a semiconductive material. Metal elements are formed on a semiconductive material at two places such that two semiconductor-metal junctions are formed. The semiconductive material with the two semiconductor-metal junctions establishes a composite resistive element having a resistance and functions as a relatively fast switch with a relatively low forward voltage drop. Each metal element may couple a terminal to the resistive element. To provide a resistive element capable of being a resistive memory element to store distinctive memory states, a ferroelectric material is provided and disposed adjacent to the semiconductive material to create an electric field from a ferroelectric dipole. The orientation of the ferroelectric dipole changes the resistance of the resistive element to allow it to function as a resistive memory element.

Abstract: Aspects disclosed include reducing or avoiding metal deposition from etching magnetic tunnel junction (MTJ) devices. In one example, a width of a bottom electrode of an MTJ device is provided to be less than a width of the MTJ stack of the MTJ device. In this manner, etching of the bottom electrode may be reduced or avoided to reduce or avoid metal redeposition as a result of over-etching the MTJ device to avoid horizontal shorts between an adjacent device(s). In another example, a seed layer is embedded in a bottom electrode of the MTJ device. In this manner, the MTJ stack is reduced in height to reduce or avoid metal redeposition as a result of over-etching the MTJ device. In another example, an MTJ device includes an embedded seed layer in a bottom electrode which also has a width less than a width of the MTJ stack.

Abstract: Tunnel magneto-resistive (TMR) sensors employing TMR devices with different magnetic field sensitivities for increased detection sensitivity are disclosed. For example, a TMR sensor may be used as a biosensor to detect the presence of biological materials. In aspects disclosed herein, free layers of at least two TMR devices in a TMR sensor are fabricated to exhibit different magnetic properties from each other (e.g., MR ratio, magnetic anisotropy, coercivity) so that each TMR device will exhibit a different change in resistance to a given magnetic stray field for increased magnetic field detection sensitivity. For example, the TMR devices may be fabricated to exhibit different magnetic properties such that one TMR device exhibits a greater change in resistance in the presence of a smaller magnetic stray field, and another TMR device exhibits a greater change in resistance in the presence of a larger magnetic stray field.

Abstract: Magneto-impedance (MI) sensors employing current confinement and exchange bias layer(s) for increased MI sensitivity are disclosed. MI sensors may be used as biosensors to detect biological materials. The sensing by the MI devices is based on a giant magneto-impedance (GMI) effect, which is very sensitive to a magnetic field. The GMI effect is a change in impedance of a magnetic material resulting from a change in skin depth of the magnetic material as a function of an external direct current (DC) magnetic field applied to the magnetic material and an alternating current (AC) current flowing through the magnetic material (or adjacent conductive materials). Thus, this change in impedance resulting from a magnetic stray field generated by magnetic nanoparticles can be detected in lower concentrations and measured to determine the amount of magnetic nanoparticles present, and thus the target analyte of interest.

Abstract: Magnetoresistive (MR) sensors employing dual MR devices for differential MR sensing are provided. These MR sensors may be used as biosensors to detect the presence of biological materials as an example. An MR sensor includes dual MR sensor devices that may be tunnel magnetoresistive (TMR) devices or giant magnetoresistive (GMR) devices as examples. The MR devices are arranged such that a channel is formed between the MR devices for receiving magnetic nanoparticles. A magnetic stray field generated by the magnetic nanoparticles causes free layers in the MR devices to rotate in opposite directions, thus causing differential resistances between the MR devices for greater sensing sensitivity. Further, as another aspect, by providing the channel between the MR devices, the magnetic stray field generated by the magnetic nanoparticles can more easily rotate the magnetic moment orientation of the free layers in the MR devices, thus further increasing sensitivity.

Abstract: A perpendicular magnetic tunnel junction (pMTJ) device includes a perpendicular reference layer, a tunnel barrier layer on a surface of the perpendicular reference layer, and a perpendicular free layer on a surface of the tunnel barrier layer. The pMTJ device also includes a dielectric passivation layer on the tunnel barrier layer and surrounding the perpendicular free layer. The pMTJ device further includes a high permeability material on the dielectric passivation layer that is configured to be magnetized by the perpendicular reference layer and to provide a stray field to the perpendicular free layer that compensates for a stray field from the perpendicular reference layer.

Abstract: A perpendicular magnetic tunnel junction may include a free layer, a reference layer, and a barrier layer. The barrier layer may be arranged between the free layer and the reference layer. The barrier layer may include a first interface and a second interface. The first interface may face the free layer, and a second interface may face the reference layer. The first interface may not physically correlate with the second interface.

Abstract: Ferroelectric-modulated Schottky non-volatile memory is disclosed. A resistive memory element is provided that is based on a semiconductive material. Metal elements are formed on a semiconductive material at two places such that two semiconductor-metal junctions are formed. The semiconductive material with the two semiconductor-metal junctions establishes a composite resistive element having a resistance and functions as a relatively fast switch with a relatively low forward voltage drop. Each metal element may couple a terminal to the resistive element. To provide a resistive element capable of being a resistive memory element to store distinctive memory states, a ferroelectric material is provided and disposed adjacent to the semiconductive material to create an electric field from a ferroelectric dipole. The orientation of the ferroelectric dipole changes the resistance of the resistive element to allow it to function as a resistive memory element.

Abstract: Exemplary features pertain to secure communications using Physical Unclonable Function (PUF) devices. Segments of a message to be encrypted are sequentially applied to a PUF device as a series of challenges to obtain a series of responses for generating a sequence of encryption keys, whereby a previous segment of the message is used to obtain a key for encrypting a subsequent segment of the message. The encrypted message is sent to a separate (receiving) device that employs a logical copy of the PUF device for decrypting the message. The logical copy of the PUF may be a lookup table or the like that maps all permissible challenges to corresponding responses for the PUF and may be generated in advance and stored in memory of the receiving device. The data to be encrypted may be further encoded to more fully exercise the PUF to enhance security. Decryption operations are also described.

Abstract: A method includes patterning a photo resist layer on top of a semiconductor device. The semiconductor device includes a lower portion, a capping layer formed on top of the lower portion, and an optional oxide layer formed on top of the capping layer. The lower portion includes a dielectric material and an interconnect. The method also includes etching portions of the semiconductor device based on the photo resist layer to expose the interconnect. The method further includes depositing a bottom electrode of a resistive memory device on the interconnect. The bottom electrode is comprised of cobalt tungsten phosphorus (CoWP).