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SOT-MRAM To Challenge SRAM


In an era of new non-volatile memory (NVM) technologies, yet another variation is poised to join the competition — a new version of MRAM called spin-orbit torque, or SOT-MRAM. What makes this one particularly interesting is the possibility that someday it could supplant SRAM arrays in systems-on-chip (SoCs) and other integrated circuits. The key advantages of SOT-MRAM technology are the pr... » read more

Outlook: DRAM, NAND, Next-Gen Memory


Jim Handy, director at Objective Analysis, sat down with Semiconductor Engineering to talk about the 3D NAND, DRAM and next-generation memory markets. What follows are excerpts of that discussion. SE: How would you characterize the NAND market thus far in 2021? Handy: All chips are seeing unusual strength in 2021, but NAND flash and DRAM are doing what they usually do by exhibiting more e... » read more

More Errors, More Correction in Memories


As memory bit cells of any type become smaller, bit error rates increase due to lower margins and process variation. This can be dealt with using error correction to account for and correct bit errors, but as more sophisticated error-correction codes (ECC) are used, it requires more silicon area, which in turn drives up the cost. Given this trend, the looming question is whether the cost of ... » read more

Reliable And Efficient Compact Models For Scalable MTJ Simulation


By Fernando García Redondo, Pranay Prabhat, and Mudit Bhargava Since its discovery in 1975, Tunnel-Magneto-Resistance (TMR) has been actively investigated. From the 2000s, advances in process technologies have made the miniaturization of Magnetic Random Access Memories (MRAMs) based on TMR devices possible, together with integration into traditional CMOS processes. Introducing magneti... » read more

New Memories Add New Faults


New non-volatile memories (NVM) bring new opportunities for changing how we use memory in systems-on-chip (SoCs), but they also add new challenges for making sure they will work as expected. These new memory types – primarily MRAM and ReRAM – rely on unique physical phenomena for storing data. That means that new test sequences and fault models may be needed before they can be released t... » read more

Convolutional Compaction-Based MRAM Fault Diagnosis


Abstract: "Spin-transfer torque magnetoresistive random-access memories (STT-MRAMs) are gradually superseding conventional SRAMs as last-level cache in System-on-Chip designs. Their manufacturing process includes trimming a reference resistance in STT-MRAM modules to reliably determine the logic values of 0 and 1 during read operations. Typically, an on-chip trimming routine consists of mult... » read more

MBIST-supported Trim Adjustment to Compensate Thermal Behavior of MRAM


Abstract: "Spin Transfer Torque Magnetic Random Access Memory (STT-MRAM) is one of the most promising candidates to replace conventional embedded memory such as Static RAM and Dynamic RAM. However, due to the small on/off ratio of MRAM cells, process variations may reduce the operating margin of a chip. Reference trimming was suggested as one of the ways to reduce variation impact to the chi... » read more

A Compact Model For Scalable MTJ Simulation


Read the full technical paper. Published June 9, 2021. Abstract This paper presents a physics-based modeling framework for the analysis and transient simulation of circuits containing Spin-Transfer Torque (STT) Magnetic Tunnel Junction (MTJ) devices. The framework provides the tools to analyze the stochastic behavior of MTJs and to generate Verilog-A compact models for their simulation in lar... » read more

A Novel Memory Test System With An Electromagnet For STT-MRAM Testing


We have successfully developed, for the first time, a new memory test system for STT-MRAM at wafer-level where an electromagnet is combined with a memory test system and a 300 mm wafer prober. In the developed memory test system, an out-of-plane magnetic field up to ±800 mT can be applied on 10 x 10 mm2 in the 300 mm wafer with distribution of less than 2.5%. We demonstrated that the electroma... » read more

MRAM Evolves In Multiple Directions


Magnetoresistive RAM (MRAM) is one of several new non-volatile memory technologies targeting broad commercial availability, but designing MRAM into chips and systems isn't as simple as adding other types of memory. MRAM isn’t an all-things-for-all-applications technology. It needs to be tuned for its intended purpose. MRAMs targeting flash will not do as well targeting SRAMs, and vice vers... » read more

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