| With the progress of science and technology and accelerating rhythm of life, the requirement of people on chip operation speed and power consumption etc is higher. Especially, the famous traditional non-volatile memories are approaching their scaling limits, so the study of new non-volatile memories is becoming more and more pressing. In the research, people found that resistance random access memory(RRAM) have a clear advantage on write/erase speed, power consumption and memory denser and etc. And the RRAM is regarded as the most promising candidate for next-generation non-volatile memories. RRAM mainly depends on the great changes in resistance to store date. In the study, we found that the sudden change of the resistance will happen in RRAM, which has metal/insulation oxide/metal structures. And the sudden change of the resistance is reversible. We have found much more switching mechanisms of the film RRAM. They are mainly consists of conduction filament, space charge limited current mechanism and schottky mechanism. But the study of the switching mechanisms is still in test phase, not form a unified theory system. In this experiment, we fabricated cuprates Pr2CuO4 film devices. We found the unipolar resistance switching, bipolar resistance switching and threshold switching behaviors. The below is the mainly show about this paper.In Chapter 2, we mainly show pulse laser deposition, magnetron sputtering, dc sputtering. And we use them to fabricate film and electrode. We also show X-ray diffraction(XRD), field emission scanning electronic microscopy(FESEM) and atomic force microscope(AFM) and etc, which are used to characterize film. And we described the working principle of them simply.In Chapter 3, we fabricated PCO ceramic target use the solid-phase reaction method. And we use XRD to prove the stability of target. Then the PCO film was grown on Pt substrate by PLD. XRD and AFM skill are used to characterize the film. Electronic characteristics of Pt/PCO/Pt device were tested by Keithey2400 source meter at room temperature. The results show the device has unipolar resistance switching. After the analysis of the XRD about PCO film and the I-V characteristics about Pt/PCO/Pt device, the change between low resistance state and high resistance state is explained in terms of conduction filament mechanism in the PCO film caused by the migration of oxygen vacancy in the electric field. And we have found that the Pt/PCO/Pt device has superior endurance and retention characteristics.In Chapter 4, the PCO film was grown on Si, Pt, STO and NSTO substrates by pulsed laser deposition. The crystalline structure and surface morphology were characterized by X-ray diffraction, scanning electronic microscopy and atomic force microscope. Different electrodes were prepared on the surface PCO films to observe various M/I/M devices. In order to observe Pt/PCO/NSTO/In device, metal In electrodes were fabricated on the reverse side of NSTO. During electronic characteristics tests of those devices, Au/PCO/Pt devices exhibit unstable unipolar resistance switching behavior; Ag(prepared by ion sputtering)/PCO/Pt devices exhibit unstable bipolar resistance switching behavior; the resistance of Ag(prepared by magnetron sputtering)/PCO/Pt devices is still in the lower resistance state; Pt/PCO/Si devices exhibit unstable unipolar resistance switching behavior, and they have higher operation voltage and power consumption; Au/PCO/Si devices exhibit unstable bipolar resistance switching behavior, and they also have higher operation voltage and power consumption; Pt/PCO//NSTO(100)/In devices exhibit stable unipolar threshold resistance switching behavior, and this behavior can be reproduced easily; but Pt/PCO//NSTO(110)/In devices exhibit unstable unipolar threshold resistance switching behavior, and it’s very hard to reproduce this behavior. The resistance switching behaviors in Au/PCO/Pt devices and Ag/PCO/Pt devices can be mainly explained in terms of asymmetric schottky barriers. There were no resistance switching behaviors in Ag(prepared by magnetron sputtering)/PCO/Pt devices due to the resistance of high purity Ag electrode prepared by magnetron sputtering is very low. Due to the single crystal Si is easy oxidized in air, the resistance change voltage of the devices which have substrate is higher. The devices with different crystal orientation NSTO substrates exhibit different switching behavior. The crystal orientation of NSTO substrates determined the crystal orientation of PCO films. And the crystal orientation of PCO films can influence the electronic characteristics of devices. Through the above comparison, different substrates and top electrodes play a key role in the resistance characteristics of the PCO devices. |
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