Role of temperature, MTJ size and pulse-width on STT-MRAM bit-error rate and backhopping

The switching voltage (Vc) variability of STT-MRAM has been investigated with respect to the effects of temperature, magnetic tunnel junction (MTJ) diameter, bias pulse-width (PW) and backhopping (BH). Arrays of STTMRAM devices having 1 transistor + 1 MTJ bitcell structure with +/- 10 nm MTJ diameters were tested under an applied ramped voltage waveform sweep at temperatures ranging from -10 degrees C to 125 degrees C with pulsewidths of 40 ns to 10 mu s. We show that the V-c distributions as a function of temperature and PW are highly skewed. BH of the MTJ bits increases with increasing temperature, longer PW and smaller MTJ diameter. We also demonstrate the switching and BH performances of 40 Mb embedded MRAM macro having different MTJ diameters.

Automated summary

The variability in switching voltage (Vc) of STT-MRAM has been studied with regards to temperature, MTJ diameter, bias pulse-width, and backhopping (BH). It was found that Vc distributions are highly skewed with temperature and pulse-width changes, while BH of the MTJ bits increases with higher temperature, longer pulse-width, and smaller MTJ diameter. The switching and BH performances of a 40 Mb embedded MRAM macro with different MTJ diameters were also demonstrated.