报道了不同厚度Ta2O5栅绝缘层对氧化锌薄膜晶体管器件性能的影响。在室温下用射频磁控溅射分别制备了100,85,60,40 nm厚度的Ta2O5 薄膜作为绝缘层的一组底栅氧化锌薄膜晶体管器件。从实验结果可以得出如下结论：随着Ta2O5栅绝缘层厚度的增加，相应器件的场效应迁移率下降，其数值分别是50.5,59.3,63.8,71.2 cm2/V·s，对应100,85,60,40 nm厚度的绝缘层。从原子力显微图像可以看到，Ta2O5薄膜表面粗糙度随着薄膜厚度的减小而降低，这是场效应迁移率得以提高的主要原因。而100,85,60,40 nm不同厚度的绝缘层相应器件的开关电流比分别是1.2×105, 4.8×105, 3.2×104, 7.2×103，其阈值电压分别为1.9,1.5,1.2,0.9 V。从各项性能综合考虑，85 nm厚度的Ta2O5栅绝缘层所制备的薄膜晶体管器件具有最佳性能。

Bottom-gate ZnO thin-film transistors (ZnO-TFTs) were fabricated with Ta2Ｏ5 film as the insulator. Ta2O5 film was grown by the radio-frequency magnetron sputtering at room temperature. The thickness of the Ta2O5 layers were 100,85,60,40 nm separately. The effect of the thickness on the performance of the ZnO-TFTs was studied. With the thickness of the insulator decreased from 100,85,60 nm to 40 nm, the field effect mobility increased from 50.5, 59.3, 63.8 to 71.2 cm2/V·s. The surface morphology of the Ta2O5 films were checked by the atomic force microscope,which showed that the root mean square (RMS) of the Ta2O5 films roughness decreases with decreasing the insulator thickness. The Ion/Ioff ratio and the threshold voltage are changed with the insulator thickness.