A semiconductor memory device includes programmable resistance memory cells and a controller which applies a forming pulse to first and second groups of the programmable resistance memory cells for inducing a change in the first group from an initial resistance range to an intermediate resistance range, and for inducing the second group having a resistance outside the intermediate range. When a forming rate is lower than a first forming threshold rate, the controller adjusts the forming pulse until the forming rate is higher than the first forming threshold rate. When a forming rate is higher than the first forming threshold rate but lower than a second forming threshold rate, the controller adjusts the forming pulse until the forming rate is higher than the second forming threshold rate. The controller applies a programming pulse to the first and second groups and generates a chip ID of the semiconductor memory device.

A non-volatile memory device comprises: a memory cell array that includes one or more memory groups each including memory cells, each of the memory cells having variable resistance value to hold a piece of data; a read circuit that, for each of the one or more memory groups, performs a read operation to obtain pieces of time information related to the memory cells in the memory group; and a data generation circuit that generates individual identification information on a basis of order of the memory cells in each of the one or more memory groups, the order corresponding to ascending order or descending order of the pieces of time information related to the memory cells in the memory group. The read circuit obtains each of the pieces of time information on a basis of a discharge phenomenon or charge phenomenon that depends on the resistance value of a corresponding one of the memory cells.

A method for generating a data set on an integrated circuit including programmable resistance memory cells includes applying a forming pulse to all members of a set of the programmable resistance memory cells. The forming pulse has a forming pulse level characterized by inducing a change in resistance in a first subset of the set from an initial resistance range to an intermediate resistance range, while after the forming pulse a second subset of the set has a resistance outside the intermediate range. The method includes applying a programming pulse to the first and second subsets. The programming pulse has a programming pulse level characterized by inducing a change in resistance of the first subset from the intermediate range to a first final range, while after the programming pulse the second subset has a resistance in a second final range, whereby the first and second subsets store said data set.

A reactive material erasure element comprising a reactive material is located between PCM cells and is in close proximity to the PCM cells. The reaction of the reactive material is trigger by a current applied by a bottom electrode which has a small contact area with the reactive material erasure element, thereby providing a high current density in the reactive material erasure element to ignite the reaction of the reactive material. Due to the close proximity of the PCM cells and the reactive material erasure element, the heat generated from the reaction of the reactive material can be effectively directed to the PCM cells to cause phase transformation of phase change material elements in the PCM cells, which in turn erases data stored in the PCM cells.

A portion of a reprogrammable storage device is used to implement permanent data storage. The storage device includes a plurality of electrically erasable memory elements and a controller. The plurality of electrically erasable memory elements are configured to store data. Each memory element is programmable a number of write cycles before reaching a write failure state. The controller is coupled to the plurality of memory elements. The controller includes a receiver and a write engine. The receiver receives an instruction to drive a selected memory element to the write failure state. The write engine repeatedly writes a data value, in a plurality of write operations, to the selected memory element until the write failure state of the selected memory element is established.

A first non-volatile memory may store first data and a second non-volatile memory may store second data. An authentication component may be coupled with the first non-volatile memory and the second non-volatile memory and may receive a request to perform an authentication operation. In response to the request to perform the authentication operation, the authentication component may access the first data stored at the first non-volatile memory and the second data stored at the second non-volatile memory and determine whether the second data stored at the second non-volatile memory has become unreliable based on a memory disturbance condition. In response to determining that the second data stored at the second non-volatile memory has become unreliable, a corrective action associated with the first data stored at the first non-volatile memory may be performed.

Endurance mechanisms are introduced for memories such as non-volatile memories for broad usage including caches, last-level cache(s), embedded memory, embedded cache, scratchpads, main memory, and storage devices. Here, non-volatile memories (NVMs) include magnetic random-access memory (MRAM), resistive RAM (ReRAM), ferroelectric RAM (FeRAM), phase-change memory (PCM), etc. In some cases, features of endurance mechanisms (e.g., randomizing mechanisms) are applicable to volatile memories such as static random-access memory (SRAM), and dynamic random-access memory (DRAM). The endurance mechanisms include a wear leveling scheme that uses index rotation, outlier compensation to handle weak bits, and random swap injection to mitigate wear out attacks.

A system and method of secure communication between computing devices based on physical unclonable functions such as memories having dissolvable conductive paths is provided. The method involves enrolling a client device, the client device having a PUF such as a pristine ReRAM. The PUF is enrolled in a secure environment by reading and storing the resistances of the PUF's addressable memory cells. The cells are categorized into “rugged” and “vulnerable” categories on the basis of their resistance, the vulnerable cells being those more likely to be permanently altered during the generations of PUF responses. The rugged cells are used for the generation of PUF responses for cryptographic key generation, but the vulnerable cells may be inspected to detect unauthorized 3rd party access to the PUF.

Example subject matter disclosed herein relates to apparatuses and/or devices, and/or various methods for use therein, in which an application of an electric potential to a circuit may be initiated and subsequently changed in response to a determination that a snapback event has occurred in a circuit. For example, a circuit may comprise a memory cell that may experience a snapback event as a result of an applied electric potential. In certain example implementations, a sense circuit may be provided which is responsive to a snapback event occurring in a memory cell to generate a feed back signal to initiate a change in an electric potential applied to the memory cell.

A random number processing device according to an aspect of the present disclosure is a random number processing device generating random number data by using data read from memory cells, the memory cells having a property such that, in a variable state, in response to application of different electrical signals, a resistance value of each of the memory cells reversibly transitions between resistance value ranges and, when the resistance value falls within at least one resistance value range among the resistance value ranges, the resistance value changes as time passes, the random number processing device including a random number processing circuit that, in operation, generates first random number data from a combination of first resistance value information and second resistance value information about the resistance values of first and second memory cells among the memory cells which fall within the at least one resistance value range.