Reactive Ion Etching as Cleaning Method Post Chemical Mechanical Polishing for Phase Change Memory Device

In order to improve nano-scale phase change memory performance, a super-clean interface should be obtained after chemical mechanical polishing (CMP) of Ge₂Sb₂Te₅ phase change films. We use reactive ion etching (RIE) as the cleaning method. The cleaning effect is analysed by scanning electron microscopy and an energy dispersive spectrometer. The results show that particle residue on the surface has been removed. Meanwhile, Ge₂Sb₂Te₅ material stoichiometric content ratios are unchanged. After the top electrode is deposited, current--voltage characteristics test demonstrates that the set threshold voltage is reduced from 13V to 2.7V and the threshold current from 0.1mA to 0.025mA. Furthermore, we analyse the RIE cleaning principle andcompare it with the ultrasonic method.