High‐Performance Solution‐Processed IGZO Thin‐Film Transistors with Al2O3/BN Composite Dielectrics Fabricated at Low Temperature

Recently, solution‐process technologies have attracted significant amounts of attention with regard to fabrication costs, and capable of large‐area deposition for various electronic devices and circuitry. In particular, solution‐processed composite dielectrics have been thoroughly investigated in an effort to improve device performance of thin‐film transistors (TFTs). Here, solution‐processed indium‐gallium‐zinc‐oxide (IGZO) TFTs with solution‐processed aluminum oxide (Al 2 O 3 ) and boron nitride (BN) composite films are reported which can be fabricated at low temperature. By optimizing the process conditions of Al 2 O 3 /BN composite dielectrics, the field‐effect mobility of an IGZO TFT is increased by a factor of 3, relative to that of pristine Al 2 O 3 dielectrics. This is a result of the improved dielectric characteristics of solution‐processed Al 2 O 3 films owing to the reduced density of the defect states. Characterization using transmittance, X‐ray photoelectron spectroscopy and direct‐current electrical measurements conclusively demonstrate that IGZO‐TFTs fabricated with energy electronically excited by microwave absorption exhibit competitive device performance with those fabricated with energy thermally activated by thermal heating at 400 °C.