In this study, we intensively investigated oxygen doped Sb2Te3 (ST-O) for high-performance phase-change memory (PCM) based on X-ray diffraction analysis and electrical measurements. The crystal became more ordered with increasing annealing temperature and the lattice deformed with the interstitial sites occupied by doped O atoms. It also exhibited that mean crystal size decreased from 8 nm to 3 nm and thus crystal growth was significantly suppressed by fine oxides due to O-doping. The resistivity of crystalline O-ST could be around 3-4 orders of magnitude higher than that of crystalline ST, which enables great reduction in reset current. It was clear that the high resistivity was able to be tuned simply by doping O into the conventional ST phase-change material for improving the performance of PCM. (C) 2015 Elsevier B.V. All rights reserved.