Hybrid cluster precursors of the LaZrO insulator for transistors: lowering the processing temperature

Solution processing of ternary and multinary amorphous metal oxide insulators at processing temperatures below 250 °C remains challenging. Here, we report that the synthesis of a hybrid cluster structure, where the metal oxide core is coordinated by ligands and the different metal elements are incorporated into one core, is an effective strategy for the low-temperature processing of the ternary LaZrO insulator. Solvothermal treatment at 160-180 °C facilitated the development of a cluster structure. From the cluster precursor, high-performance insulating LaZrO films were obtained at 200 °C under the irradiation of ultraviolet light. The analysis data indicate that the solvothermal treatment led to structural unification of the metal oxide network and facilitated stabilization of the residual organic ingredients in UV annealing, which both contributed to the improved insulating properties of LaZrO. Together with a solution-processed channel, we have been able to fabricate LaZrO-based transistors at 200 °C. Though the channel material has not been optimized, the transistor have showed a low gate leakage current around 10 pA at an operating voltage of 15 V, an on/off ratio of near 10⁶, a field-effect saturation mobility of 0.37 cm² V^-1 s^-1, a subthreshold swing factor of 0.61 V decade^-1.