Everspin Technologies | Date: 2015-05-01
In one aspect, the present inventions are directed to a magnetoresistive structure having a tunnel junction, and a process for manufacturing such a structure. The tunnel barrier may be formed between a free layer and a fixed layer in a plurality of repeating process of depositing a metal material and oxidizing at least a portion of the metal material. Where the tunnel barrier is formed by deposition of at least three metal materials interceded by an associated oxidization thereof, the oxidation dose associated with the second metal material may be greater than the oxidation doses associated with the first and third metal materials. In certain embodiments, the fixed layer may include a discontinuous layer of a metal, for example, Ta, in the fixed layer between two layers of a ferromagnetic material.
Everspin Technologies | Date: 2015-01-13
In some examples, a memory device is configured to receive a precharge command and an activate command. The memory device performs a first series of events related to the precharge command in response to receiving the precharge command and a second series of events related to the activate command in response to receiving the activate command. The memory device delays the start of the second series of events until the first series of events completes.
Everspin Technologies | Date: 2015-10-20
A cell bias control circuit maximizes the performance of devices in the read/write path of memory cells (magnetic tunnel junction device+transistor) without exceeding leakage current or reliability limits by automatically adjusting multiple control inputs of the read/write path at the memory array according to predefined profiles over supply voltage, temperature, and process corner variations by applying any specific reference parameter profiles to the memory array.
Everspin Technologies | Date: 2015-10-21
Circuitry and a method for regulating voltages applied to magnetoresistive bit cells of a spin-torque magnetoresistive random access memory (ST-MRAM) reduces time-dependent dielectric breakdown stress of the word line transistors. During a read or write operation, only the ends of the selected bit cells are pulled down to a low voltage and/or pulled up to a high voltage depending on the operation (write 0, write 1, and read) being performed. The ends of the unselected bit cells are held at a precharge voltage while separately timed signals pull up or pull down the ends of the selected bit cells during read and write operations.
Everspin Technologies | Date: 2015-06-02
In some examples, a memory device may be configured to read or write multiple bit cells as part of the same operation. In some cases, the tunnel junctions forming the bit cells may be arranged to utilize shared read/write circuitry. For instance, the tunnel junctions may be arranged such that both tunnel junctions may be written using the same write voltages. In some cases, the bit cells may be configured such that each bit cell is driven to the same state, while in other cases, select bit cells may be driven high, while others are driven low.