Preparation And Study Of Zinc Oxide Based Multiple Metal Oxide Resistive Switching

With the rapid development of memory, the scale of tranditional Flash are approaching its physical limitation. Resistive Random Access Memory(RRAM) is considered as one of the most potential competitors for the next generation of non-volatile high density memory, because of its simple structure, low power consumption, high reading and writing speed, high storage density as well as good compatibility with CMOS process. As the most popular dielectric layer material of resistive switching, metal oxide thin films became the hot-spot of the resistive switching(RS) research field due to its good resistive switching characteristic, but the resistive switching’s repeatability and stability problem still need to be solved for further practical application of RRAM technique, and the resistive switching mechanism need to be make a clear consensus. Therefore, we studied preparation and properties of multiple metal oxide thin film based on Zn O.In this thesis, InGaZnO(IGZO) thin films were deposited on different substrates(such as glass, sapphire, polyimide, quartz, monocrystalline silicon, etc.) by Radio Frequency magnetron sputtering. Cu or Al were evaporated as the top electrode. The Al doped ZnO(AZO) was deposited as bottom electrode. The Metal/IGZO/AZO sandwich structure resistive switching devices were prepared. The effects of the deposition temperature, the ratio of argon, oxygen and the thickness on IGZO resistive switching characteristics were studied in this paper.In addition, the influence of different embedded layers on IGZO resistive switching was studied. The CuO/IGZO dual dielectric layer resistive switching which has more than 102 On/Off current ratio and good stability was prepared. IGZO and CuO/IGZO dual dielectric layer resistive switching’s I-V curve obey Ohmic’s law in low voltage region; Current is proportional to V2 in the high voltage region and the result means that the I-V curve obey Child’s Law. The resistive switching mechanism could be explained by the trap-controlled space charge limited conduction model. The effects of different metallic top electrode on resistive properties can be explained by metal-semiconductor conduct barrier model. The schottky barrier and the heterojunction formed when CuO embedded layer conduct with Cu electrode and IGZO film layer. The schottky barrier and the heterojunction effect turned the CuO layer to be a electronic collection layer. It can improved the On/Off current ratio of IGZO resistive switching.In chapter five, we introduced the CuGaZnO(CGZO) thin film resistive switching device which was prepared on quartz substrate and the flexible polyimide substrate. The preparation process parameters including deposition temperature and ratio of argon oxygen of CGZO film resistive switching were discussed as well. The ratio of argon and oxygen has significant effect on CGZO resistive switching characteristic, so the oxygen vacancy which migrated and formed conductive filaments in dielectric layer could explain the resistive switching mechanism of those device.In a conclusion, IGZO resistive switching in the cycle of 103 tests showed an excellent anti-fatigue property. But IGZO resistive switching has a large threshold voltage( ? 4V). CuO embedded layer can improve the IGZO resistive switching’s On/Off current ratio to over 102. The CGZO resistive switching On flexible substrate not only has a large On/Off current ratio(102), but also has a small threshold voltage( ?2V). It means that the CGZO resistive switching On flexible substrate had a lower power consumption and wider range of application than IGZO resistive switching.