A ferroelectric memory structure including a first conductive line, a second conductive line, and a memory cell is provided. The second conductive line is disposed on the first conductive line. The memory cell is disposed between the first and second conductive lines. The memory cell includes a switch device and a ferroelectric capacitor structure. The switch device is disposed between the first and second conductive lines. The ferroelectric capacitor structure is disposed between the first conductive line and the switch device. The ferroelectric capacitor structure includes ferroelectric capacitors electrically connected. Each of the ferroelectric capacitors includes a first conductive layer, a second conductive layer, and a ferroelectric material layer. The second conductive layer is disposed on the first conductive layer. The ferroelectric material layer is disposed between the first conductive layer and the second conductive layer. The ferroelectric material layers in the ferroelectric capacitors have different top-view areas.

Technologies relating to CMOS image sensors with integrated Resistive Random-Access Memory (RRAMs) units that provide energy efficient analog storage, ultra-high speed analog storage, and in-memory computing functions are disclosed. An example CMOS image sensor with integrated RRAM crossbar array circuit includes a CMOS image sensor having multiple pixels configured to receive image signals; a column decoder configured to select the pixels in columns to read out; a row decoder configured to select the pixels in rows to read out; an amplifier configured to amplify first signals received from the CMOS image sensor; a multiplexer configured to sequentially or serially read out second signals received from the amplifier; and a first RRAM crossbar array circuit configured to store third signals received from the multiplexer.

A storage device includes a first electrode, a second electrode, and a storage layer. The second electrode is disposed to oppose the first electrode. The storage layer is provided between the first electrode and the second electrode, and includes one or more chalcogen elements selected from tellurium (Te), selenium (Se), and sulfur (S), transition metal, and oxygen. The storage layer has a non-linear resistance characteristic, and the storage layer is caused to be in a low-resistance state by setting an application voltage to be equal to or higher than a predetermined threshold voltage and is caused to be in a high-resistance state by setting the application voltage to be lower than the predetermined threshold voltage to thereby have a rectification characteristic.

A neuromorphic memory circuit including a memory cell with a programmable resistive memory element. A postsynaptic capacitor builds up a leaky integrate and fire (LIF) charge. An axon LIF pulse generator activates a LIF discharge path from the postsynaptic capacitor through the resistive memory element when the axon LIF pulse generator generates axon LIF pulses. A postsynaptic comparator compares the capacitor voltage to a threshold voltage and generates postsynaptic output pulses when the capacitor voltage passes the threshold voltage. The postsynaptic output pulses include a postsynaptic firing characteristic dependent on a frequency of the axon LIF pulses. A refractory circuit prevents the postsynaptic comparator from generating additional postsynaptic output pulses until a refractory time passes since a preceding postsynaptic output pulse. A training circuit adjusts the postsynaptic firing characteristic to match a target firing characteristic.

A method of forming an array of cross point memory cells comprises using two, and only two, masking steps to collectively pattern within the array spaced lower first lines, spaced upper second lines which cross the first lines, and individual programmable devices between the first lines and the second lines where such cross that have an upwardly open generally U-shape vertical cross-section of programmable material laterally between immediately adjacent of the first lines beneath individual of the upper second lines. Arrays of cross point memory cells independent of method of manufacture are disclosed.

A method and a circuit for reading resistive states of memory elements within crossbar arrays includes a first crossbar array having first sets of row firms and column lines, with memory elements disposed at the intersections between the row lines and the column lines, a second crossbar array having second sets of row lines and column lines, with memory elements disposed at the intersections between the row lines and the column lines, and a comparator having a first input connected to the first crossbar array and a second input connected to the second crossbar array, wherein the first input is configured to receive a sense voltage from as select column in the first crossbar array and the second input is configured to receive a reference voltage from a corresponding select column in the second crossbar array.

A computer implemented method includes updating weight values associated with a plurality of analog synapses in a cross-bar array that implements an artificial neural network by sending a pulse sequence to the analog synapses. Each analog synapse includes a conductance unit, wherein a weight value of the analog synapse is based on a conductance value of the conductance unit. The pulse sequence changes the conductance value. The method further includes comparing the weight values of the analog synapses with target weight values associated with the analog synapses and selecting a set of analog synapses based on the comparison. The method further includes updating the weight values of the selected analog synapses by sending a set of electric pulses of varying durations.

A method to adaptively and dynamically set a bias scheme of a crossbar array for a write operation includes: performing a read-before-write operation to determine a number of cells n to be written during a write operation; comparing n to a predetermined threshold value to determine an efficient bias scheme; setting at least one voltage regulator to provide a bias voltage according to the efficient bias scheme; and performing the write operation. A method to determine threshold value to determine an efficient bias scheme of a crossbar array and an energy efficient crossbar array device are also described.

A ferroelectric memory structure including a first conductive line, a second conductive line, and a memory cell is provided. The second conductive line is disposed on the first conductive line. The memory cell is disposed between the first and second conductive lines. The memory cell includes a switch device and a ferroelectric capacitor structure. The switch device is disposed between the first and second conductive lines. The ferroelectric capacitor structure is disposed between the first conductive line and the switch device. The ferroelectric capacitor structure includes ferroelectric capacitors electrically connected. Each of the ferroelectric capacitors includes a first conductive layer, a second conductive layer, and a ferroelectric material layer. The second conductive layer is disposed on the first conductive layer. The ferroelectric material layer is disposed between the first conductive layer and the second conductive layer. The ferroelectric material layers in the ferroelectric capacitors have different top-view areas.

A nonvolatile memory cell includes a resistance-change nonvolatile memory element 50 and a selection transistor TR. One end of the nonvolatile memory element 50 is connected to one source/drain region 15A of the selection transistor TR and is connected to a write line WR. The other source/drain region 15B of the selection transistor TR is connected to a select line SL. The other end of the nonvolatile memory element 50 is connected to a bit line BL.