MRAM device formation with in-situ encapsulation

A method of forming a magnetic random access memory (MRAM) device, the method comprising the steps of:

• patterning an MRAM stack disposed on a dielectric into individual memory cell stacks, wherein the MRAM stack comprises a bottom electrode disposed on the dielectric, a magnetic tunnel junction (MTJ) disposed on the bottom electrode, and a top electrode disposed on the MTJ, and wherein the patterning of the MRAM stack is performed using an intermediate angle ion beam etch (IBE) landing on the dielectric;
• removing redeposited metal from sidewalls of the memory cell stacks using a high angle IBE, wherein the redeposited metal results from the patterning of the MRAM stack;
• redepositing the dielectric along the sidewalls of the memory cell stacks using a low angle IBE to form a first layer of dielectric encapsulating the memory cell stacks;
• and
• depositing a second layer of dielectric encapsulating the memory cell stacks, wherein the first layer of dielectric and the second layer of dielectric form a bilayer dielectric spacer structure along the sidewalls of the memory cell stacks,
• wherein the patterning of the MRAM stack, the removing of the redeposited metal, and the redepositing of the dielectric along the sidewalls of the memory cell stacks steps are all performed in-situ in a vacuum chamber, without breaking vacuum.