Reactive-ion etching of Sn-doped Ge2Sb2Te5 in CHF3/O2 plasma for non-volatile phase-change memory device

The reactive-ion etching of Sn-doped Ge2Sb2Te5 (GST) films with different Sn concentration in CHF3/O2 plasma was studied. By changing the gas mixture ratio and radio-frequency (RF) power under constant chamber pressure, the relatively smooth surface morphologies of etched Sn-doped GST were obtained. The characteristics of etch rate as functions of gas mixture, chamber pressure, and RF power were also investigated. Besides that, the etching selectivity of Sn-doped GST to SiO2 and photoresist was measured.