Zinc oxide thin film transistors using MgO–Bi1.5Zn1.0Nb1.5O7 composite gate insulator on glass substrate

We report on high mobility ZnO thin film transistors (TFTs) (< 5 V), utilizing a room temperature grown MgO–Bi1.5Zn1.0Nb1.5O7 (BZN) composite gate insulator on a glass substrate. 30 mol% MgO added BZN composite gate insulators exhibited greatly enhanced leakage current characteristics (~< 2 × 10− 8 A/cm2 at 0.3 MV/cm) due to the high breakdown strength of MgO, while retaining an appropriate high-k dielectric constant of 32. The ZnO-TFTs with MgO–BZN composite gate insulators showed a high field-effect mobility of 37.2 cm2/Vs, a reasonable on–off ratio of 1.54 × 105, a subthreshold swing of 460 mV/dec, and a low threshold voltage of 1.7 V.