Title: Analysis of self-heating of thermally assisted spin-transfer torque magnetic random access memory

Abstract

Thermal assistance has been shown to significantly reduce the required operation power for spin torque transfer magnetic random access memory (STT-MRAM). Proposed heating methods include modified material stack compositions that result in increased self-heating or external heat sources. Here, we analyze the self-heating process of a standard perpendicular magnetic anisotropy STT-MRAM device through numerical simulations in order to understand the relative contributions of Joule, thermoelectric Peltier and Thomson, and tunneling junction heating. A 2D rotationally symmetric numerical model is used to solve the coupled electro-thermal equations including thermoelectric effects and heat absorbed or released at the tunneling junction. We compare self-heating for different common passivation materials, positive and negative electrical current polarity, and different device thermal anchoring and boundaries resistance configurations. The variations considered are found to result in significant differences in maximum temperatures reached. Average increases of 3 K, 10 K, and 100 K for different passivation materials, positive and negative polarity, and different thermal anchoring configurations, respectively, are observed. Furthermore, the highest temperatures, up to 424 K, are obtained for silicon dioxide as the passivation material, positive polarity, and low thermal anchoring with thermal boundary resistance configurations. Interestingly it is also found that due to the tunneling heat,more » Peltier effect, device geometry, and numerous interfacial layers around the magnetic tunnel junction (MTJ), most of the heat is dissipated on the lower potential side of the magnetic junction. We have observed this asymmetry in heating and is important as thermally assisted switching requires heating of the free layer specifically and this will be significantly different for the two polarity operations, set and reset.« less

Authors:

Deschenes, Austin ^[1]; Muneer, Sadid ^[1]; Akbulut, Mustafa ^[1]; Gokirmak, Ali ^[1]; Silva, Helena ^[1]

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+ Show Author Affiliations

1. Univ. of Connecticut, Storrs, CT (United States). Electrical Engineering

Publication Date:

Fri Nov 11 00:00:00 EST 2016

Research Org.:

Univ. of Connecticut, Storrs, CT (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES); National Science Foundation (NSF)

OSTI Identifier:

1361518

Grant/Contract Number:  

SC0005038

Resource Type:

Accepted Manuscript

Journal Name:

Beilstein Journal of Nanotechnology

Additional Journal Information:

Journal Volume: 7; Journal ID: ISSN 2190-4286

Publisher:

Beilstein Institute

Country of Publication:

United States

Language:

English

Subject:

77 NANOSCIENCE AND NANOTECHNOLOGY; FEM modeling; Joule heating; self-heating; spin torque transfer magnetic random access memory (STT-MRAM); thermoelectrics