A memory device includes a plurality of magnetoresistive random-access memory (MRAM) cells including a first one-time programmable (OTP) MRAM cell. A first OTP select transistor is connected to the first OTP MRAM cell. The first OTP select transistor configured to selectively apply a breakdown current to the first OTP MRAM cell to write the first OTP MRAM cell to a breakdown state.

Memory devices provide a plurality of memory cells, each memory cell including a memory element and a selection device. A plurality of first (e.g., row) address lines can be adjacent (e.g., under) a first side of at least some cells of the plurality. A plurality of second (e.g., column) address lines extend across the plurality of row address lines, each column address line being adjacent (e.g., over) a second, opposing side of at least some of the cells. Control circuitry can be configured to selectively apply a read voltage or a write voltage substantially simultaneously to the address lines. Systems including such memory devices and methods of accessing a plurality of cells at least substantially simultaneously are also provided.

An electronic device is provided to comprise a semiconductor memory unit that comprises: a substrate including active regions, which are extended in a second direction and disposed from each other in a first direction; a plurality of gates extended in the first direction and across with the active regions; a lower contact disposed in both sides of gates and coupling the active regions in the first direction; an upper contact of the lower contact overlapping with the active region out of the active regions in a side of each gate, and overlapping with the active regions in the other side of each gate; and first and second interconnection lines coupled to the upper contact, extended in the second direction, and being alternately disposed from each other in the first direction, wherein the upper contact of a side of the gates has a zigzag shape in a first oblique direction.

A circuit includes an operational amplifier including an inverting input terminal capacitively coupled to each of an OTP cell array and an NVM cell array and first and second output terminals, an ADC coupled to the first and second output terminals, thereby configured to receive a differential output voltage from the operational amplifier, and a comparator coupled to the ADC and configured to output a data bit responsive to a digital output signal received from the ADC. The circuit is configured to cause the operational amplifier to generate the differential output voltage based on each of a current received from an OTP cell of the OTP cell array and a voltage received from an NVM cell of the NVM cell array.

Concurrent access of multiple memory cells in a cross-point memory array is disclosed. In one aspect, a forced current approach is used in which, while a select voltage is applied to a selected bit line, an access current is driven separately through each selected word line to concurrently drive the access current separately through each selected memory cell. Hence, multiple memory cells are concurrently accessed. In some aspects, the memory cells are accessed using a self-referenced read (SRR), which improves read margin. Concurrently accessing more than one memory cell in a cross-point memory array improves bandwidth. Moreover, such concurrent accessing allows the memory system to be constructed with fewer, but larger cross-point arrays, which increases array efficiency. Moreover, concurrent access as disclosed herein is compatible with memory cells such as MRAM which require bipolar operation.

A magnetic multilayer film for a magnetic memory element includes an amorphous heavy metal layer having a multilayer structure in which a plurality of first layers containing Hf alternate repeatedly with a plurality of second layers containing a heavy metal excluding Hf; and a recording layer that includes a ferromagnetic layer and that is adjacent to the heavy metal layer, the ferromagnetic layer having a variable magnetization direction.

A memory device includes a spin-orbit-transfer (SOT) bottom electrode, an SOT ferromagnetic free layer, a first tunnel barrier layer, a spin-transfer-torque (STT) ferromagnetic free layer, a second tunnel barrier layer and a reference layer. The SOT ferromagnetic free layer is over the SOT bottom electrode. The SOT ferromagnetic free layer has a magnetic orientation switchable by the SOT bottom electrode using a spin Hall effect or Rashba effect. The first tunnel barrier layer is over the SOT ferromagnetic free layer. The STT ferromagnetic free layer is over the first tunnel barrier layer and has a magnetic orientation switchable using an STT effect. The second tunnel barrier layer is over the STT ferromagnetic free layer. The second tunnel barrier layer has a thickness different from a thickness of the first tunnel barrier layer. The reference layer is over the second tunnel barrier layer and has a fixed magnetic orientation.

Disclosed is a memory structure with reference-free single-ended sensing. The structure includes an array of non-volatile memory (NVM) cells (e.g., resistance programmable NVM cells) and a sense circuit connected to the array via a data line and a column decoder. The sense circuit includes field effect transistors (FETs) connected in parallel between an output node and a switch and inverters connected between the data line and the gates of the FETs, respectively. To determine the logic value of a stored bit, the inverters are used to detect whether or not a voltage drop occurs on the data line within a predetermined period of time. Using redundant inverters to control redundant FETs connected to the output node increases the likelihood that the occurrence of the voltage drop will be detected and captured at the output node, even in the presence of process and/or thermal variations. Also disclosed is a sensing method.

Systems and methods for adapting garbage collection (GC) operations in a memory device to a pattern of host accessing the device are discussed. The host access pattern can be represented by how frequent the device is in idle states free of active host access. An exemplary memory device includes a memory controller to track a count of idle periods during a specified time window, and to adjust an amount of memory space to be freed by a GC operation in accordance with the count of idle periods. The memory controller can also dynamically reallocate a portion of the memory cells between a single level cell (SLC) cache and a multi-level cell (MLC) storage according to the count of idle periods during the specified time window.

In one embodiment, the magnetic memory device includes a free layer structure having a variable magnetization direction. The free layer structure includes a first free layer, the first free layer being a first Heusler alloy; a coupling layer on the first free layer, the coupling layer including a metal oxide layer; and a second free layer on the metal oxide layer, the second free layer being a second Heusler alloy, the second Heusler alloy being different from the first Heusler alloy.