| Summary: | 碩士 === 長庚大學 === 電子工程學系 === 104 === In this thesis, bipolar resistive switching (BRS) characteristics using W/SiO2/TiN and Ir/SiO2/TiN RRAM structure have been investigated. Complementary resistive switching (CRS) using Ir/SiO2/TiN single cell has also been demonstrated. Defective SiO2 switching material is confirmed by X-ray photoelectron spectroscopy. Typical BRS are shown in W/SiO2/TiN stack at the current compliances of 500 µA and 200 µA. Statistical analysis is done by taking randomly 50 devices which confirm that device-to-device switching uniformity is ˃ 75%. In case of W/SiO2/TiN, the low resistance state (LRS) current shows Ohmic conduction, and high resistance state (HRS) current shows Schottky emission at low field and hopping conduction at higher field. On the other hand, both HRS and LRS show Ohmic conduction at low field, and hoping conduction is observed at higher field by using Ir/SiO2/TiN structure. The SiO2 thickness based BRS characteristics have been explained. In addition, good data retention of > 3hr and long read endurance of >106 cycles with a small pulse width of 1µs are observed. Resistive switching mechanism using W and Ir electrode is explained by oxygen ions migration under external bias has been explained by schematic model. The CRS is observed by tuning proper bias in Ir/SiO2/TiN single cell without metal interlayer. In CRS, low field and high field regimes are complied with space-charge limited current (SCLC) and Fowler-Nordheim (F-N) tunneling mechanism, respectively. The CRS mechanism has been explained considering oxygen ions migration or vacancy (VO) mediated filamentary schematic model. Superior read endurance of ˃104 cycles is obtained at small pulse width of 1 µs with acceptable resistance ratio of ~10. The non-linearity factor of >10 is also obtained, which is useful for future three-dimensional (3D) crossbar memory applications.
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