Lateral spin valve device for magnetic reader applications fabricated by an Etch back process

A schematic design of the device with lithography defined pillars and channel is shown. The deposited film stacks have a structure of substrate/Cu(100 nm)/Co(20 nm)/Ta(4 nm). The films were deposited in vacuum with a Shamrock sputtering system. Patterning was performed using a Vistec electron beam (e-beam) lithography system. The channel was first patterned using negative resist and ion milling. After resist removal, negative resist and ion milling were used again to pattern and define the pillars. Before the e-beam resist was moved, SiO2 was deposited using e-beam evaporation to isolate the pillars and prevent shorting between top electrodes and the channel. The e-beam resist was then removed to expose the tops of the pillars for electrical contact. A final step of e-beam lithography was performed to pattern the top electrodes. E-beam evaporation was used to deposit Ti(10nm)/Au(100 nm) for the top electrodes. A schematic of the fabrication process is shown. Precise alignment between the multiple steps of e-beam lithography for the electrodes, FM pillars, and channel is essential for correct operation of the device.