Effects of Intense Pulsed Light (IPL) Rapid Annealing and Back-Channel Passivation on Solution-Processed In-Ga-Zn-O Thin Film Transistors Array

We report on the effects of the intense pulsed light (IPL) rapid annealing process and back-channel passivation on the solution-processed In-Ga-Zn-O (IGZO) thin film transistors (TFTs) array. To improve the electrical properties, stability and uniformity of IGZO TFTs, the oxide channel layers were treated by IPL at atmospheric ambient and passivated by photo-sensitive polyimide (PSPI). When we treated the IGZO channel layer by the IPL rapid annealing process, saturation field effect mobility and subthreshold swing (S.S.) were improved. And, to protect the back-channel of oxide channel layers from oxygen and water molecules, we passivated TFT devices with photo-sensitive polyimide. The IGZO TFTs on glass substrate treated by IPL rapid annealing without PSPI passivation showed the field effect mobility (μFE) of 1.54 cm2/Vs and subthreshold swing (S.S.) of 0.708 V/decade. The PSPI-passivated IGZO TFTs showed higher μFE of 2.17 cm2/Vs than that of device without passivation process and improved S.S. of 0.225 V/decade. By using a simple and fast intense pulsed light treatment with an appropriate back-channel passivation layer, we could improve the electrical characteristics and hysteresis of IGZO-TFTs. We also showed the improved uniformity of electrical characteristics for IGZO TFT devices in the area of 10 × 40 mm2. Since this IPL rapid annealing process could be performed at a low temperature, it can be applied to flexible electronics on plastic substrates in the near future.