Study On The Resistive Switching Properties Of The HfO_x Thin Film

This article examines the RRAM focus on Hf O2 metal oxide material, because of its preparation process is simple and the components are compatible with existing CMOS processes. Hf O2-based materials in the resistive memory, from a plurality of angles we analyzed the structure of the device to improve device performance means. Details of the preparation of experiments to study the different electrical measurement methods and material thickness of the data retention characteristics and stability characteristics of the impact. This test mainly carried out based on the terms of Hf O2, Ta Ox / Hf O2 material RRAM device resistance change characteristics and mechanisms of resistance change research. Studies as follows:To further enhance the Pt / Hf O2 / Pt memory device performance, in order to obtain a high uniformity and low resistivity, the effects of different operating voltage of the electrical properties of Hf O2 films prepared and found that in a negative voltage operation Hf O2 film performance has been greatly improved, and consistent with the theoretical basis.Pt / Ta Ox / Hf O2 / Pt resistive device is a multi-state memory, it confirmed that the device is capable of maintaining a stable three-impedance state, so that the device can be well preserved, "0" by Retention Performance Test, "1" and "2" three storage value. And the level of resistance of the device than the great resistance state transition occurs, the high-impedance state resistance value(RHRS) and low resistance state resistance values(RLRS) ratio are each about 104 times, so the circuit can be very good differentiate each storage condition. And the voltage resistance transitions relative concentration is conducive with a relatively fixed voltage value read and write to the device. We think it is a common mechanism of action resistive effect by the filaments and SCLC effects.On the size of the problem Ti / Hf Ox / Pt device was studied the influence of different Ti electrode thickness of Ti / Hf Ox / Pt resistive device performance, we believe that since the mobile device and the oxygen vacancies of oxygen ions, so the device which led to the formation of filaments device is turned on. Study found that when Ti layer thickness decreases, open voltage decreases, but when Ti electrodes 2nm, may all be oxidized, resulting in a large number of oxygen vacancies, it is easy to breakdown. When Ti electrode thick, the device showed a good stability of the resistance varying characteristics, we believe is due to oxygen ions Ti electrode similar to a library that can be deposited into a sufficient number of oxygen ions, so the fatigue characteristics of the device better.