A method is presented for forming an on-chip security key. The method includes electrically connecting a pair of phase change memory (PCM) elements in series, electrically connecting a programming transistor to the pair of PCM elements, electrically connecting an input of an inverter to a common node of the pair of PCM elements, setting the PCM elements to a low resistance state (LRS) in an initialization stage, applying a RESET pulse to generate a security bit and to cause one of the PCM elements to change to a high resistance state (HRS), and generating a logic “1” or “0” at the output of the inverter.

A semiconductor device including at least one variable resistance device is provided. A variable resistance element includes: an ion supply layer having a top, a bottom and a sidewall connecting the top to the bottom; an ion-receiving layer having an inner sidewall connected to at least a portion of the sidewall of the ion supply layer; a gate pattern connected to an outer sidewall of the ion-receiving layer; and a source pattern connected to one of the top or bottom of the ion supply layer, and a drain pattern connected to the other one or the top or bottom of the ion supply layer. A resistance of the ion supply layer is varies depending on an amount of ions supplied from the ion supply layer to the ion-receiving layer in response to a voltage applied to the gate pattern.

A nonvolatile memory cell includes a semiconductor layer including a first recess and a second recess. A first gate insulation layer is disposed on a bottom surface and side surfaces of the first recess. A second gate insulation layer is disposed on a bottom surface and side surfaces of the second recess. A variable resistive material layer is disposed on a first region of the semiconductor layer disposed between the first and second recesses. An insulation barrier layer disposed on a top surface and side surfaces of the variable resistive material layer. A gate electrode surrounding the insulation barrier layer and extending to fill the first and second recesses.

Technologies relating to controlling forming process in RRAM devices implemented in a cross-bar circuit using one or more feedback circuits are disclosed. An example apparatus includes an RRAM cell configured to form a channel; a MOSFET having a drain terminal, a source terminal, and a gate terminal, wherein the MOSFET is connected to the RRAM cell via the drain terminal; a TIA connected to the MOSFET via the source terminal; a first signal generator connected to the RRAM cell; a second signal generator connected to the MOSFET via the gate terminal; and a comparator having a first input end, a second input end, and an output end, wherein the comparator is connected to the TIA via the first input end, the second input end is connected to a reference voltage source, and the output end is connected to the first signal generator and the second signal generator.

A semiconductor device according to an embodiment includes a substrate, a gate structure disposed on the substrate, a hole pattern penetrating the gate structure on the substrate, and a first variable resistance layer, a second variable resistance layer, and a channel layer sequentially disposed on a sidewall surface of the gate structure. The gate structure includes at least one gate electrode layer and at least one interlayer insulation layer that are alternately stacked. The first and second variable resistance layers include ions exchangeable with each other.

A method of setting multi-state memory elements into at least one low-power state may include receiving a command to cause a memory element to transition into one of three or more states; applying a first signal to the memory element to transition the memory element into the one of the three or more states, where the three or more states are evenly spaced in a portion of an operating range of the memory element; receiving a command to cause a memory element to transition into a low-power state; applying a second signal to the memory element to transition the memory element into the low-power state, where the low-power state is outside of the portion of the operating range of the memory element by an amount greater than a space between each of the three or more states.

A nonvolatile memory device includes a substrate having an upper surface and a channel structure disposed over the substrate. The channel structure includes at least one channel layer pattern and at least one interlayer insulation layer pattern, which are alternately stacked in a first direction perpendicular to the upper surface, and the channel structure extends in a second direction perpendicular to the first direction. The nonvolatile memory device includes a resistance change layer disposed over the substrate and on at least a portion of one sidewall surface of the channel structure, a gate insulation layer disposed over the substrate and on the resistance change layer, and a plurality of gate line structures disposed over the substrate, each contacting a first surface of the gate insulation layer and disposed to be spaced apart from each other in the second direction.

A semiconductor device including a variable resistance device is provided. A variable resistance element according to one embodiment of the present disclosure includes: an ion-receiving layer having a top, a bottom and a sidewall connecting the top to the bottom; an ion supply layer having an inner sidewall connected to at least a portion of the sidewall of the ion-receiving layer; a gate pattern connected to an outer sidewall of the ion supply layer; and a source pattern connected to one of the top or bottom of the ion-receiving layer, and a drain pattern connected to the other one of the top or bottom of the ion-receiving layer, wherein a resistance of the ion-receiving layer varies depending on an amount of ions supplied from the ion supply layer based on a voltage applied to the gate pattern.

The gate of the access transistor of a 1 transistor 1 resistor (1T1R) type RRAM cell is biased relative to the source of the access transistor using a current mirror. Under the influence of a voltage applied across the 1T1R cell (e.g., via the bit line), the RRAM memory element switches from a higher resistance to a lower resistance. As the RRAM memory element switches from the higher resistance to the lower resistance, the current through the RRAM cell switches from being substantially determined by the higher resistance of the RRAM device (while the access transistor is operating in the linear region) to being substantially determined by the saturation region operating point of the access transistor.

Described are apparatuses for improving resistive memory energy efficiency. An apparatus performs data-driven write to make use of asymmetric write switch energy between write0 and write1 operations. The apparatus comprises: a resistive memory cell coupled to a bit line and a select line; a first pass-gate coupled to the bit line; a second pass-gate coupled to the select line; and a multiplexer operable by input data, the multiplexer to provide a control signal to the first and second pass-gates or to write drivers according to logic level of the input data. An apparatus comprises circuit for performing read before write operation which avoids unnecessary writes with an initial low power read operation. An apparatus comprises circuit to perform self-controlled write operation which stops the write operation as soon as bit-cell flips. An apparatus comprises circuit for performing self-controlled read operation which stops read operation as soon as data is detected.