Current hysteresis by oxygen vacancy exchange between oxides in Pt/a-IGZO/TaO x /W

•We investigated current hysteresis mechanism in Pt/a-IGZO/TaOx/W structure that shows rectifying characteristics.•In order to understand the role of each layer and the origin of memory effect, we designed and performed two model experiments on the basis of preliminary experimental results and analysis.•Current hysteresis (memory effect) is attributed to the bias dependent resistance change in TaOx layer due to positively charged oxygen vacancy exchange between two oxides.