MRAM with lamellar structure as free layer

The key factors to improve the switching characteristics are systematically analyzed to develop high density MRAM with a reliable operating margin. We demonstrated that roughness control of MTJ films, choice of free layer materials with small Ms, and optimized cell shape can effectively suppress the switching distribution. As a novel free layer scheme, a lamellar structure is proposed and found to improve the switching characteristics by suppressing the grain growth in the ferromagnetic layer.