Magnetic Tunnel Junction Performance Under Mechanical Strain

TL;DR

This study assesses how mechanical stress impacts magnetic tunnel junctions with perpendicular magnetic anisotropy, finding minimal performance variation under stress up to wafer breakage.

Contribution

We developed a novel 4-point bending setup to measure MTJ performance parameters under mechanical stress, demonstrating their robustness.

Findings

Less than 2% variation in TMR, switching current, and thermal stability under stress.

MTJ performance remains stable up to wafer breakage.

Mechanical stress has negligible effect on device performance.

Abstract

In this work we investigate the effect of the mechanical stress on the performance of magnetic tunnel junctions (MTJ) with perpendicular magnetic anisotropy. We developed a 4-point bending setup, that allows us to apply a constant stress over a large substrate area with access to electrical measurements and external magnetic field. This setup enables us to measure key device performance parameters, such as tunnel magnetoresistance (TMR), switching current ($I_c^{50\%}$) and thermal stability ($\Delta$), as a function of applied stress. We find that variations in these parameters are negligible: less than $\SI{2}{\percent}$ over the entire measured range between the zero stress condition and the maximum stress at the point of wafer breakage.