Exploring variability and reliability of multi-level STT-MRAM cells

Abstract

In this paper we have presented a comprehensive analysis of multi-valued STT-MRAM and their benefits and drawbacks. Results shows that in order to reduce read failures in scaled geometries, self-reference reading scheme is necessary. We have also shown that by choosing appropriate RA <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sub> and RA <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> (we define the feasible RA <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sub> -RA <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> region in the design space), one can reduce both read and write failures. However, in order to achieve higher reliability, a thicker T ox is needed, which can further constrain the RA <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sub> -RA <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> design space of multi-valued STT-MRAMs.