Preparation of ZnO Transparent Conductive Thin Films by ARE

A zinc oxide film has been used for surface acoustic were (SAW) device, ultrasonic wave microscope，ultrasonic filter and transparent conductive film as practical electronic materials. and resentrapid development of the electronic technologies needs zinc oxide films with improved properties.控制crystallographic orientation is especially necessary for the应用程序到ultrasonicSeveral fabrication techniques of zinc oxide films have been reported such as the chemicalvapor deposition technique (CVD), the dc or rf sputteringECR sputtering and the ion plating.The activated active evaporation (ARE) method can preparethe ZnO films with excellent properties and high orientationbecause the evaporation rale of Zn metal is controlled.In this study，zinc oxide films were prepared on silica glass substrates by the use of an r.f.c activated reactiveevaporation ARE method，X-ray diffraction (XRD) and scanning electron microscope (SEM). The electricalconductivity of the films and the doping effect of Al ions also investigated.XRD measurementsindicate that the films were c-axis oriented and that an r.f.p rasma of Zn and O was必需ZnO film deposition. Substrate temperature, oxygen gas pressure, evaporation rate，r.f.power and Al doping amount affect the c-axis orientation, the growth rate，the microstructure of the films and electrical conductivity. Optimum conditions with a fine textureof the surface and having good crystallinity as well as good conductivity （*10^<-4> OMEGA cm）follows: substrate temperatue；200゚C, total evaporation rate；1.0*/s, the oxygen pressure2.0*10 Torr, the r.f.power；250w and the Al evaporation rate ratio；2-6%. The films with 1.0*10 <-3>OMEGA cm were prepared at 50゚C for The substrate temperature。

A zinc oxide film has been used for surface acoustic were (SAW) device, ultrasonic wave microscope, ultrasonic filter and transparent conductive film as practical electronic materials. And resent rapid development of the electronic technologies needs zinc oxide films with improved properties. Control of crystallographic orientation is especially necessary for the application to ultrasonic devices. Several fabrication techniques of zinc oxide films have been reported such as the chemical vapor deposition technique (CVD), the dc or rf sputtering, the ECR sputtering and the ion plating.The activated reactive evaporation (ARE) method can prepare the ZnO films with excellent properties and high orientation, because the evaporation rale of Zn metal is well controlled.In this study, zinc oxide films were prepared on silica glass substrates by the use of an r.f.activated reactive evaporation ARE method, and were examined by X-ray diffraction (XRD) and scanning electron microscope (SEM). The electrical conductivity of the films and the doping effect of Al ions were also investigated.XRD measurements indicate that the films were c-axis oriented and that an r.f.plasma of Zn and O was necessary for the ZnO film deposition. Substrate temperature, oxygen gas pressure, evaporation rate, r.f.power and Al doping amount affect the c-axis orientation, the growth rate, the microstructure of the films and electrical conductivity. Optimum conditions with a fine texture of the surface and having good crystallinity as well as good conductivity (*10^<-4> OMEGA・cm) were as follows : the substrate temperatue ; 200ﾟC,the total evaporation rate ; 1.0*/s, the oxygen pressure ; 2.0*10^<-4> Torr, the r.f.power ; 250W and the Al evaporation rate ratio ; 2-6%. The films with 1.0*10^<-3>OMEGA・cm were prepared at 50ﾟC for the substrate temperature.