We report the effect of a rapid thermal annealing process (RTP) on the electrical properties of an aluminum‐doped indium zinc tin oxide (Al‐IZTO) thin film transistor (TFT) with a back‐channel etched (BCE) structure. First, the RTP temperatures were varied from 250 to 350 °C, and their effect on Al‐IZTO TFT was investigated. The 250 °C RTP produced the best transfer characteristics (subthreshold swing = 0.11 V/dec, hysteresis = −0.25 V, and mobility = 26.42 cm2 V−1s−1), and as the temperature increased, the TFTs showed slightly degraded properties in hysteresis and subthreshold swing. Through the transmission line method (TLM), the channel shortening effect and contact properties according to the annealing temperature were studied. The reliability against a negative gate bias stress under illumination (NBIS) was also analyzed. At high RTP temperature (>300 °C), stability under NBIS was considerably improved, and the 350 °C RTP device showed turn‐on voltage shift of −1.7 V. The microwave photoconductivity decay (μ‐PCD) method revealed that the RTP effectively reduced shallow localized states, which enhanced the NBIS stability at high temperature. Finally, the RTP was compared with the conventional furnace process at the same temperature in terms of transfer characteristics and uniformity. Even with a much shorter process time for the RTP, Al‐IZTO TFTs exhibited similar or better transfer properties and uniformity to or than the furnace annealing.

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In the oxide thin film transistors (TFTs), annealing process is necessary to improve its electrical properties, and generally performed by a furnace and an oven. Compared with them, rapid thermal process (RTP) can serve several advantages including much reduced process time and improved uniformity, which are more important factors in mass-production industry. In addition to near-infrared (NIR) lamp, generally used as a heat source, ultra-violet (UV) and deep-ultra-violet (DUV) light sources can also be used in RTP system, and they can provide much higher energy, giving the possibility of more effective and efficient annealing. Herein, we studied the annealing effect of RTP system utilizing UV and DUV light source on the electrical properties of back-channel etched aluminum-doped indium zinc tin oxide thin film transistors (Al-IZTO BCE TFTs). Author KeywordsOxide thin film transistor; Rapid thermal process (RTP); UV and DUV annealing effect P-19 / Y. Nam SID 2018 DIGEST • 1249 ISSN 0097-996X/18/4703-1249-$1.00 © 2018 SID Figure 5. Evolution of transfer curves under (a) PBTS (V gs =+1.0MV/cm, T=60 o C, Time=10000s) and NBTS ((V gs =-1.0MV/cm, T=60 o C, Time=10000s) for the Al-ITZTO TFTs with 1 st annealing using RTP-NIR, UV/NIR, and DUV/NIR annealing.

We report the effect of a rapid thermal annealing process (RTP) on the ion dopant activation process in LTPS TFT on PI substrate and on the electrical properties of Al-doped InZnSnO thin film transistor (TFT) with back-channel etched BCE structure.