The formation and oxidation of the core-shell Ge/GeO x nanofilament by external bias leads to the resistive switching characteristics. Figure 7 Typical I – V hysteresis characteristics of as-deposited and PMA devices with an IrO x /GeO x /W structure. Figure 8 Formation (a) and oxidation (b) of Ge/GeO Caspase Inhibitor VI in vitro x nanofilaments under SET and RESET operations. Ge/GeO x nanowires can be formed under SET and it is Selleck GSK1210151A dissolved under RESET operations. Figure 9a shows that the IrO x /GeO x /W memory devices possess good data retention

characteristics before and after annealing under a low CC of 100 μA. Initially, the LRS and HRS values are 57 kΩ and 97.9 MΩ for the PMA device, respectively, whereas they are 115.7 kΩ and 46.2 MΩ ACP-196 research buy for the as-deposited device, respectively. After 104 s, the LRS and HRS values of the PMA device are almost the same (60.2 kΩ and 93.5 MΩ, respectively), whereas the LRS of the as-deposited device is almost the same (116.5 kΩ) but the HRS decreases (37.8 MΩ). Therefore, the resistance ratio losses after 104 s are 18.5% (399 to 325) and 9.5% (1,717 to 1,553) for the as-deposited and PMA devices, respectively. After applying a program/erase current of 500 μA, a long read endurance of >105 cycles with a stress pulse of 500 μs and a read voltage of 0.1V is obtained, as shown in Figure 9b. Figure 9 Data retention characteristics

and good pulse read endurance. (a) Data retention characteristics of the IrO x /GeO x /W devices. The resistance ratio is larger for the PMA devices than that of the as-deposited one after 104 s. (b) Good pulse read endurance of >105 cycles is obtained for the PMA devices. The PMA device shows better performance Leukotriene-A4 hydrolase than that of the as-deposited device, which makes it suitable for nanoscale nonvolatile memory applications. The diameter of the nanofilament was calculated using a new method for oxide-based RRAM devices as follows. Figure 10 shows the soft breakdown (SBD) of the GeO x film by applying constant current stress on the TE. The stress current is 100 μA, and the voltage is monitored with time. The initial voltage is high (30 to 34 V), and this suddenly jumps to a low

voltage of 6 to 7.5 V for the device-to-device measurement. Because the external constant current stress changes the GeO x film from insulating to the defect-rich layer or conducting by Ge-O bond breaking, the voltage across the GeO x film is reduced. Due to this Ge-O bond breaking, the conducting path or filament is formed, the current passes easily, and the voltage across the film drops. By observing the voltage drop, it is confirmed that the conducting filament is formed. Definitely, high current stress is not for resistive switching because of strong conducting path formation, which is hard to do RESET operation. By the capture and emission of electrons at an oxide trap inside the GeO x film, voltage shifts (ΔV i) of 18 to 23.5 V are observed.