High-Performance a-IGZO TFT Fabricated With Ultralow Thermal Budget via Microwave Annealing

In this work, we report high-performance amorphous indium gallium zinc oxide (a-IGZO) thin-film transistors (TFTs) with atomic layer deposited Al₂O₃ dielectric processed at a minimal temperature of 189.6 °C via microwave annealing (MWA). The a-IGZO TFT with MWA exhibits an improvement of 57% in subthreshold swing (SS) compared with the unannealed device; meanwhile, it retains high field-effect mobility of up to 29.2 cm²/(V $\cdot $ s) and large switching ratio of >10⁸. Moreover, the SS of the device was further reduced through a two-step MWA treatment. It is believed that MWA treatment effectively reduces the density of trap states associated with oxygen vacancies, promotes the formation of lattice oxygen, and thus improves the quality of IGZO film. MWA with low thermal budget shows great potential in applications of the back-end of line (BEOL)-compatible oxide devices.