| As an amorous oxide semiconductor material,indium aluminum zinc oxide(IAZO)has the advantages of wide band gap with large modulation range,excellent optoelectronic properties,and relatively low cost.Although researchers have conducted some research on IAZO thin films and their thin film transistors(TFTs),especially IAZO TFTs with excellent performance have been prepared by the RF magnetron sputtering process,but there are few studies on the preparation of IAZO thin films by the pulsed laser deposition(PLD)method and the film properties are relatively ordinary.In addition,we have not seen other research reports on IAZO SBD except our group’s research on the preparation of IAZO Schottky barrier diode(SBD,briefly called Schottky diode)by RF magnetron sputtering.Therefore,it is of great significance to study and optimize the preparation process and properties of IAZO thin films by the PLD method and explore their application in SBD to promote the development and application of IAZO thin films.In this context,IAZO thin films were prepared by the PLD method.The effects of oxygen pressure,substrate temperature and vacuum annealing treatment on the properties of IAZO thin films were systematically studied,and the fabrication process and properties of IAZO SBD devices were also studied.The main research contents and results of this thesis are as follows:(1)Effects of oxygen pressureIAZO thin films were prepared by PLD under different oxygen pressure conditions,and the effects of oxygen pressure on the structure and component,surface morphology,optical properties and electrical properties of the thin films were studied.Based on various parameters,the IAZO thin films grown under the optimal conditions were used in Schottky diodes,and their electrical properties were tested.The results showed that changing the oxygen pressure had no effect on the structure of the IAZO films,but had an effect on the element content and surface morphology of the films,as well as the optical transmittance,forbidden band width,carrier concentration and mobility of the films.The IAZO film prepared under 0.6Pa oxygen pressure had the best electrical properties,with the carrier concentration of 1.12×1018 cm-3,the Hall mobility of 23.9 cm2/V·s and the resistivity of 2.33×10-1Ω·cm.We then applied the films grown under the optimal oxygen pressure to SBD,and achieved good Schottky contacts and device performance after annealing in air,and the rectification ratio reached 2.21 × 104.(2)Effects of substrate temperatureIAZO thin films were prepared by PLD at different substrate temperatures.The structure and component,surface morphology,optical properties and electrical properties of the thin films were studied.And the application of IAZO thin films prepared under the optimal substrate temperature in Schottky diode was also investigated.The results showed that the substrate temperature had little effect on the structure and component of IAZO films,and the roughness and optical transmittance of the films were generally good.The IAZO film prepared at 100℃ had the best electrical properties,with the carrier concentration of 1.15×1018cm-3,the Hall mobility of 25.3 cm2/V·s and the resistivity of 2.15×10-1 Ω·cm.Then,we applied the films grown under the optimal conditions to SBD.The Schottky contact was achieved after annealing in air,and the rectification ratio reached the order of 103.(3)Effects of vacuum annealing treatmentIAZO thin films were prepared by PLD and the films were vacuum annealed to study the changes of their properties.The results showed that the vacuum annealing treatment did not change the amorphous structure of the films,and the vacuum annealing treatment at certain temperature helped to lower the surface roughness,reduce the internal defect states,and improve the optical and electrical properties of the films.The IAZO thin film annealed in vacuum at 400℃ had the best electrical properties,with the carrier concentration of 7.23×1017cm-3,the Hall mobility of 13.8 cm2/V·s and the resistivity of 6.25×10-1Ω·cm. |
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