Reactive Ion Etching Characteristics of Permalloy Thin Films

Abstract

Permalloy thin films were reactive ion etched using CO and NH3 gases. The dependence of etching rate on various etching conditions (e. g. gas flow rate, gas pressure, CO/NH3 ratio, etc.) was investigated. Changes in magnetic properties with etching were also investigated. Etching rate remains nearly constant at about 100&Aring/min regardless of gas flow rate when only NH3 gas is used. In the case of CO and a mixture of CO/NH3, etching rate depends on etching condition and the fraction of gas mixture. As the thickness of permalloy thin films decreases by etching, coercivity increases. The coercivity increase is larger for NH, than for CO or CO/NH3. Change in the magnetic properties is mainly due to surface roughness and etching related damages.