Method to make MRAM with small footprint
OwnerYimin Guoinventor
Life of this patent
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Abstract
A method to make magnetic random access memory with small footprint using O-ion implantation to form electrically isolated memory pillar and electric (bottom and top) leads, which are made from some oxygen gettering materials, Mg, Zr, Y, Th, Ti, Al, Ba. The doped O-ions react with metal atoms to form fully oxidized metal oxide after high temperature anneal. The method only needs two photolithography patterning and oxygen implantations and no etch and dielectric refill are needed, thus significantly reduce process cost. The method can produce extremely small MRAM cell size with perfectly vertical pillar edges (FIG. 1).
Claims15
A method to make a high density magnetic random access memory (HDMRAM) comprising:
- a deposition process of a magnetic tunnel junction (MTJ) multilayer film on a substrate surface connecting VIAs of select transistors of a control circuitry;
- a doping process of oxygen gettering materials into the MTJ multilayer film;
- a first photolithography patterning process to form a first hard mask in a first direction on the MTJ multilayer film;
- a first oxygen ion implantation process to implant oxygen atoms into the MTJ multilayer film regions uncovered by the first hard mask;
- a second photolithography patterning process to form a second hard mask in a second direction on the MTJ multilayer film;
- a second oxygen ion implantation process to implant oxygen atoms into the MTJ multilayer film regions uncovered by the second hard mask;
- a thermal annealing process for oxidizing and transforming the MTJ multilayer film regions uncovered by either the first hard mask or the second hard mask into electrical insulation regions on the substrate and forming small footprint MRAM elements covered by both the first hard mask and the second hard mask, and a high density MTJ array.
Dependencies are inferred from the claim text.