Researchers at Tohoku University have developed tips for a single-nanometer magnetic tunnel junction (MTJ), permitting for efficiency tailoring to satisfy the necessities of numerous functions, starting from AI/IoT to vehicles and house applied sciences.

The breakthrough will result in high-performance spintronic non-volatile reminiscence, appropriate with state-of-the-art semiconductor applied sciences. The particulars had been published within the journal npj Spintronics on January 4, 2024.

The key attribute of non-volatile reminiscence is its skill to retain information within the absence of an exterior energy supply. Consequently, intensive growth efforts have been directed in the direction of non-volatile reminiscence due to its skill to cut back energy consumption in semiconductor built-in circuits (ICs). Performance necessities for non-volatile reminiscence range in keeping with particular functions. For occasion, AI/IoT functions demand high-speed efficiency, whereas automotive and house applied sciences prioritize excessive retention capabilities.

Spin-transfer torque magnetoresistive random entry reminiscence (STT-MRAM), a sort of non-volatile memory know-how that shops information by using the intrinsic angular momentum of electrons, often known as spin, possesses the potential to handle a few of the limitations related to current reminiscence applied sciences.

The primary constructing block of STT-MRAM is the magnetic tunnel junction (MTJ): two ferromagnetic layers separated by a skinny insulating barrier. Scientists have lengthy tried to satisfy the problem of constructing MTJs smaller whereas assembly efficiency necessities, however many issues stay.

STT-MRAM, using MTJs with dimensions within the vary of a number of tens of nanometers, has been efficiently developed for automotive semiconductors utilizing 1X nm know-how nodes. Looking forward to future nodes, nevertheless, there’s a have to scale down MTJs to single-digit nanometers, or X nm, whereas guaranteeing the potential to tailor efficiency in keeping with particular functions.

To do that, the analysis group designed a method to engineer single-nanometer MTJs with a CoFeB/MgO stack construction, a de facto customary materials system. Varying the person CoFeB layer thickness and the variety of [CoFeB/MgO] stacks allowed them to regulate the form and interfacial anisotropies independently—one thing essential for reaching high-retention and high-speed capabilities, respectively.

As a consequence, the MTJ efficiency will be tailor-made for functions starting from retention-critical to speed-critical. At the scale of single nanometers, shape-anisotropy enhanced MTJs demonstrated excessive retention (> 10 years) at 150°C, whereas interfacial-anisotropy enhanced MTJs achieved quick velocity switching (10 ns or shorter) beneath 1 V.

“Since the proposed structure can be adapted to existing facilities in major semiconductor factories, we believe that our study provides a significant contribution to the future scaling of STT-MRAM,” mentioned Junta Igarashi, one of many lead authors of the examine.

Principal Investigator Shunsuke Fukami added that “Semiconductor industries generally tend to be conscious of long-lasting scaling. In that sense, I think this work should send a strong message to them that they can rely on the future of STT-MRAM to help usher in a low-carbon society.”