Preparation and varistor behaviors of AZO/Bi2O3 composite film
Film varistors are important in the applications of the microcircuits and integrated circuit protection.Here,the composite films based on aluminum doped zinc oxide(AZO)and bismuth oxide(Bi2O3)were prepared with magnetron sputtering method.The effects of Bi2O3 depositing time and annealing temperature on the varistor characteristics of the samples were investigated with the AZO/Bi2O3/AZO configuration.The experimental results indicate that AZO/Bi2O3 composite films possess obvious varistor characteristics.As the depositing time of the Bi2O3 layer increasing,the varistor nonlinear coefficient of the composite film first increases and then decreases while the varistor voltage maintains an increasing trend.When the depositing time of Bi2O3 layer is 15 min,the varistor nonlinear coefficient of the composite film annealed at 600 ℃ in air for 1 h is 28.4,the corresponding varistor voltage is 7.1 V and the leakage current is 0.059 mA.With the annealing temperature increasing from 500 ℃ to 700 ℃,the varistor nonlinear coefficient of the composite film sample can reach 38.4 and the corresponding leakage current decreases to 0.044 mA while the varistor voltage increases to 10.4 V.This work provides an experimental reference for the pursuit of new film varistor materials.
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