Patent ID: 8087157

Claim:
A process to manufacture a magnetic tunnel junction (MTJ) read head, comprising: on a substrate, depositing a lower conductive lead; in succession, depositing on said lower conductive lead, a first pinning layer, a first pinned layer, a dielectric tunneling layer, and a free layer, thereby forming a MTJ stack; on the free layer, forming an etch mask that defines a pedestal; then, using a beam that consists only of xenon ions, ion milling said mask and MTJ stack until a part of said MTJ stack, no more than about 0.1 microns thick, has been removed and said pedestal, having sidewalls with a vertical section that includes all of said free layer, has been formed; on the mask and on said second pinning layer, depositing an isolation dielectric layer whose top surface is above that of said MTJ stack; then removing said mask, thereby exposing said free layer; and depositing an upper conductive lead.