Advanced MTJ Stack Engineering of STT-MRAM to Realize High Speed Applications

We demonstrate superior data retention of 1 month at 125°C with improved switching efficiency at 10 ns write time without back-hopping failure. The 40Mb macro having the advanced MTJ stacks show wide operating temperature range from -40 to 125°C with the read margin even up to 150°C and zero fail bit count with ECC on. Our study indicates that the tight switching voltage distribution and the coherent switching are essential not only for fast switching but also back-hopping margin improvement. Furthermore, our paper shows an engineering pathway how advanced MTJ stack engineering can improve key device parameters.