FERROMAGNETIC TUNNEL JUNCTION RANDOM ACCESS MEMORY, SPIN VALVE RANDOM-ACCESS MEMORY, SINGLE FERROMAGNETIC FILM RANDOM-ACCESS MEMORY AND MEMORY CELL ARRAY USING THEM

摘要

PROBLEM TO BE SOLVED: To stably perform a write operation and a read operation by a method wherein a ferromagnetic layer which constitutes a ferromagnetic tunnel junction or a spin valve junction is formed annularly, so that the direction of magnetization of the ferromagnetic layer is not changed by a closure magnetic field even when a magnetic random-access memory is made fine. SOLUTION: A conductive plug 45 which is composed of a nonmagnetic metal is formed so as to pass a ferromagnetic layer 42, a tunnel insulating film 43 and a ferromagnetic layer 44. A first bit line BL1 is connected to one end of the conductive plug 45, and a word line WL is connected to the other end. When a write current is made to flow to the conductive plug 45 constituted in this manner, the ferromagnetic layer 42 can be magnetized in the right-handed direction or its reverse left-handed direction. Then, when an antiferromagnetic film pattern 46 out of those of the ferromagnetic layer 44 is carried by a part which is away from the conductive plug 45, the direction of the magnetization of the ferromagnetic layer 44 is pinned.