Unipolar resistive switching in Au / Cr / Mg 0 . 84 Zn 0 . 16 O 2 − δ / p +

Unipolar resistive switching memory cells were fabricated using a Mg0.84Zn0.16O2−δ thin film, sandwiched between p+-Si (100) substrate and Cr/Au top electrodes. Electrical measurements showed a large memory window and memory window margin of 107 and 104, respectively. Furthermore, a wide switching voltage distribution gap of 3.6 V between the switching-ON and -OFF processes was obtained for different sweeping cycles. Gas bubbles at four different stages were observed on the top electrodes after electrical stimulus, indicating that conducting filaments consisting of oxygen vacancies are responsible for the resistive switching characteristics. Conductive atomic force microscopy results show that the highly conductive areas are along the edge of the gas bubble or the edge of the device. This phenomenon suggests the potential of scaling down the device area to lower than 32 nm.