Optimizing Photonic Annealing Technique for High-k Dielectric of Full-Solution-Processed Oxide Thin Film Transistor

In this article, it is demonstrated that the photonic annealing process of ultraviolet (UV) irradiation or rapid thermal annealing (RTA)-assisted LA technique can effectively enhance the bias and illumination stability of full-solution-processed oxide thin film transistor (TFT). Although both post-annealing treatments have comparable effects, UV irradiation has relatively less heat loss and time consumption of only 3 min, compared to the RTA process that heats at a temperature of 400 °C and holds 10 min. Depending on the laser annealing (LA)/UV technique, the amorphous hafnium-aluminum oxide (HAO) dielectric thin film exhibits a smooth surface with an rms value of 0.293 nm, a high optical bandgap of 6.19 eV, and good dielectric performance with high dielectric constants of 12.9, low leakage current densities, and high breakdown field of about 4 MV/cm. Moreover, full-solution-processed indium-tin-oxide (ITO)–HAO–tungsten-zinc-tin-oxide (WZTO) TFT shows excellent overall properties with the mobility (
$\mu $
) of 10.65 cm
$^{{2}}\cdot \text{V}^{-{1}}\cdot \text{s}^{-{1}}$
, subthreshold swing (SS) of 198 mV/dec. And the device has good bias and illumination stability, especially the threshold voltage (
${V}_{T}$
) shifts are all less than 3 V under positive bias illumination stress (PBIS) and negative bias illumination stress (NBIS) testing for 10000 s. These indicate the potential for the photonic annealing process of the UV-assisted LA technique on improving the stability of the full-solution-processed TFTs, which is attributed to high-throughput fabrication for large-area, transparent, and flexible electronics.