Effect of interfacial oxide layer on the switching uniformity of Ge ₂Sb₂Te₅-based resistive change memory devices

We report the effect of the interfacial oxide layer on switching uniformity in Ge₂Sb₂Te₅ (GST)-based resistive switching memory devices. An interfacial oxide layer acting as an internal resistor was fabricated by the simple thermal oxidation process at low temperature and confirmed by x-ray photoelectron spectroscopy analysis. TiN/oxidized GST/GST/Pt devices showed extremely uniform resistance states owing to intentionally controlled current flow induced by the interfacial oxide layer, despite the filaments being randomly formed. Furthermore, the devices showed good memory performance, e.g., a large on/off resistance ratio (over four orders of magnitude) and reliable data retention (up to 10⁴ s at 85 C).