Patent ID: 7218556

Claim:
A method of writing to a magnetic random access memory (MRAM) device, comprising: preparing a digit line disposed on a semiconductor substrate, a bit line crossing over the digit line, and a magnetic tunnel junction (MTJ) interposed between the digit line and the bit line, the MTJ having a pinned layer, a tunneling insulating layer and a synthetic anti-ferromagnetic (SAF) free layer which are sequentially stacked, the SAF free layer having a bottom free layer and a top free layer which are separated by an exchange spacer layer; and applying a first write line pulse to one of the digit line and the bit line, in which a first positive current pulse is turned on at a time t 2 and turned off at a time t 5 , and a second write line pulse, to the other of the digit line and the bit line, in which a second positive current pulse is turned on at a time t 1 and turned off at a time t 3 , and a negative current pulse is turned on at a time t 4 and turned off at a time t 6 .