Investigation Of Si Based Ga₂O₃ Thin Film Resistive Memory

The rapid development of science and technology has led to the continuous decline of the feature size of microelectronic devices,and a series of bottleneck problems faced by traditional Flash memory has given birth to the development of a new generation of memory devices.Resistive variable memory（RRAM）has a unique place due to its simple structure,high storage density,fast read and write speed,and compatibility with traditional process lines.The third-generation wide-bandgap semiconductor material,gallium oxide（Ga₂O₃）,has become a powerful development target for RRAM due to its wide band gap,oxygen sensitivity and low cost.However,the current Ga₂O₃ RRAM still has many problems such as unstable operating voltage,large reset current,forming voltage,and discrete parameters.Aiming at these problems,this paper mainly prepares gallium oxide RRAM on Si-based substrate by magnetron sputtering,and studies its resistance-switching properties.Firstly,Ga₂O₃ RRAM was fabricated on Si substrate by magnetron sputtering,and the effects of magnetron sputtering parameters,such as sputtering power,pressure,argon-oxygen ratio,etc.,on the performance of RRAM were studied.At the same time,the effect of magnetron sputtering parameters on the content of oxygen vacancies in the as-grown Ga₂O₃ films was analyzed by X-ray photoelectron spectroscopy（XPS）,because it directly affects the performance of RRAM.In addition,the sputtering rate and the crystal state of Ga₂O₃ thin films under different power,as well as the surface roughness were obtained.The effects of annealing and electrode size on resistive switching characteristics were also studied.The final optimization found that under the conditions of 120 W,0.6 Pa,and 10%argon-to-oxygen ratio,the Ga₂O₃ RRAM had the largest storage window and excellent cycle characteristics.And under this condition,the Forming process also disappears.Secondly,by regulating the Si-based Pt substrate,and under the conditions of 120 W,0.6 Pa,and 10%argon-to-oxygen ratio,it was found that the single-layer Ga₂O₃ thin film RRAM can achieve bipolar and unipolar coexistence and reversible switching under the same current confinement.The effect of different annealing atmosphere and annealing time on the performance of single-bipolar Ga₂O₃ RRAM was further studied,and it was concluded that the single-bipolar performance of Ga₂O₃ RRAM device was the best under the annealing conditions of 200℃and 10 min in N₂.Under this condition,both unipolar and bipolar devices of the device showed excellent holding characteristics,which remained stable in the10⁴ s test;and the set voltage(V_Set)was concentrated at 0.5 V.By comparing the parameters of unipolar and bipolar,it is found that the window,setting voltage and reset voltage and current of unipolar are larger than those of bipolar.It is verified that bipolar is electric field reset,and unipolar is Joule heat reset.physical mechanism.Through XPS analysis and low-resistance variable temperature test,it is concluded that the conductive channels formed inside the device are dominated by Ag,but the role of oxygen vacancies cannot be ignored.The current conduction mechanism of the two polarities is analyzed,and it is concluded that when the device is in the low resistance state,the conduction mechanism is the conductive filament model,while the unipolar conduction mechanism in the high resistance state is space charge limited current,bipolar The characteristic is the combined effect of the ohmic mechanism and the Schottky emission mechanism.Finally,the high-resistance state stability of the device is further optimized by inserting a Cu nanoburied layer,reducing the operating voltage and current.Both the set and reset voltages drop to around 150 m V,and the reset current drops below 0.5 m A.The mechanism of buried layer oxidation and the diffusion of buried layer atoms under the action of an electric field are proposed to explain this change and confirmed in the phenomenon that the window becomes larger in the cycle characteristics.The effects of the thickness of the buried layer on the properties of Ga₂O₃ RRAM devices are compared,and the proposed explanation mechanism is proved from another aspect.Performance optimization plays a role in reducing power consumption.