A 4K-400K Wide Operating-Temperature-Range MRAM Technology with Ultrathin Composite Free Layer and Magnesium Spacer.

A universal MRAM technology is proposed to fulfill versatile applications ranging from quantum computing to automotive electronics across a wide operating temperature range of 4K to 400K. An ultrathin (1.4 nm) CoFeB composite free layer with an Mg spacer is designed to enlarge breakdown voltage and write margin, decrease switching current, and maintain thermal stability and magnetoresistance ratio at all temperatures. High endurance (>10 ¹¹ ) and excellent reliability (write margin > 0.4 V) are achieved from 4K to 400K without compromising speed (10 ns) and retention (10 years at 300K).