US Patent 11937512 Magnetic tunnel junction device with air gap

A semiconductor device including a magnetic tunnel junction stack, a metallic hard mask aligned above the magnetic tunnel junction stack and an air gap surrounding the metallic hard mask. A method including forming a magnetic tunnel junction stack, forming a metallic hard mask aligned above the magnetic tunnel junction stack, conformally forming a dielectric over the metallic hard mask and the magnetic tunnel junction stack, forming barrier on vertical side surfaces of the dielectric, and removing the dielectric between the metallic hard mask and the barrier. A method including forming a magnetic tunnel junction stack, forming a metallic hard mask aligned above the magnetic tunnel junction stack, conformally forming a dielectric over the metallic hard mask and the magnetic tunnel junction stack, selectively removing a portion of the dielectric surrounding the metallic hard mark.