Fabrication of spin-valve sensors with quarter micron trackwidth using a double-layer resist system

We report the fabrication methods of vertical type spin-valve (SV) sensors with a quarter micron trackwidth using electron beam lithography and ion beam etching. A double-layer resist system which simultaneously solves the problems of resist residuals and the redepositions have been investigated. This method was successfully applied to fabricate IrMn-SV sensors with a 250 nm trackwidth. Transfer curve measurements showed degradation of GMR ratio from 11% to 7% after fabrication. However, this degradation was not thought inherent to this process.