Abstract
•BER variability of STT-MRAM for LRS to HRS switching increases with bias pulse-width.•Backhopping BER increases with temperature and bias pulse-width.
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 STT-MRAM 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 °C to 125 °C with pulsewidths of 40 ns to 10 µs. We show that the Vc 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.