Chemically robust solution-processed indium zinc oxide thin film transistors fabricated by back channel wet-etched Mo electrodes

Abstract

We designed a systematic processing strategy for solution-processed indium zinc oxide thin film transistors (TFTs) with chemically wet-etched Mo electrodes and chemically durable channels prepared by a sol–gel method. First, we explored the effect of H₂O₂ wet-etchant pH to define efficiently wet-etched Mo source/drain electrodes without Mo residues and with minimal chemical damage to the indium zinc oxide (IZO) channel. Next, sufficient condensation reaction times and a two-step engineering process were performed on the solution-processed IZO thin films to improve their inferior chemical durability (from incomplete metal oxygen bonds and low film density). The solution-processed IZO channels with wet chemical patterning and superior chemical durability preserved the original electrical transfer properties with minimal electrical degradation in the back channel etch (BCE) processes. Finally, additional N₂ post-annealing partially recovered the field-effect mobility (2.5 cm² V⁻¹ s⁻¹), and on-current without oxidation of the Mo electrode, comparable to the lift-off processed TFTs. This approach provides a significant potential for using wet-based BCE processes in sol–gel prepared oxide TFTs.