Lim Kiwon, Choi Pyungho, Kim Sangsub, Kim Hyunki, Kim Minsoo, Lee Jeonghyun, Hyeon Younghwan, Koo Kwangjun, Choi Byoungdeog
College of Information and Communication Engineering, Sungkyunkwan University, Suwon 16419, Republic of Korea.
J Nanosci Nanotechnol. 2018 Sep 1;18(9):5913-5918. doi: 10.1166/jnn.2018.15596.
Double stacked indium-zinc oxide (IZO)/zinc-tin oxide (ZTO) active layers were employed in amorphous-oxide-semiconductor thin-film transistors (AOS TFTs). Channel layers of the TFTs were optimized by varying the molarity of ZTO back channel layers (0.05, 0.1, 0.2, 0.3 M) and the electrical properties of IZO/ZTO double stacked TFTs were compared to single IZO and ZTO TFTs with varying the molarity and molar ratio. On the basis of the results, IZO/ZTO (0.1 M) TFTs showed the excellent electrical properties of saturation mobility (13.6 cm2/V·s), on-off ratio (7×106), and subthreshold swing (0.223 V/decade) compared to ZTO (0.1 M) of 0.73 cm2/V · s, 1 × 107, 0.416 V/decade and IZO (0.04 M) of 0.10 cm2/V · s, 5 × 106, 0.60 V/decade, respectively. This may be attributed to diffusing Sn into front layer during annealing process. In addition, with varying molarity of ZTO back channel layer, from 0.1 M to 0.3 M ZTO back channel TFTs, electrical properties and positive bias stability deteriorated with increasing molarity of back channel layer because of increasing total trap states. On the other hand, 0.05 M ZTO back channel TFT had inferior electrical properties than that of 0.1 M ZTO back channel TFT. It was related to back channel effect because of having thin thickness of channel layer. Among these devices, 0.1 M ZTO back channel TFT had a lowest total trap density, outstanding electrical properties and stability. Therefore, we recommended IZO/ZTO (0.1 M) TFT as a promising channel structure for advanced display applications.
非晶氧化物半导体薄膜晶体管（AOS TFTs）采用了双层堆叠的铟锌氧化物（IZO）/锌锡氧化物（ZTO）有源层。通过改变ZTO背沟道层的摩尔浓度（0.05、0.1、0.2、0.3 M）对TFTs的沟道层进行优化，并将IZO/ZTO双层堆叠TFTs的电学性能与不同摩尔浓度和摩尔比的单一IZO和ZTO TFTs进行比较。基于这些结果，与ZTO（0.1 M）的饱和迁移率（0.73 cm2/V·s）、开/关比（1×107）和亚阈值摆幅（0.416 V/十倍频程）以及IZO（0.04 M）的饱和迁移率（0.10 cm2/V·s）、开/关比（5×106）和亚阈值摆幅（0.60 V/十倍频程）相比，IZO/ZTO（0.1 M）TFTs表现出优异的电学性能，饱和迁移率为13.6 cm2/V·s、开/关比为7×106、亚阈值摆幅为0.223 V/十倍频程。这可能归因于在退火过程中Sn扩散到前层。此外，随着ZTO背沟道层摩尔浓度从0.1 M增加到0.3 M，由于总陷阱态增加，ZTO背沟道TFTs的电学性能和正偏压稳定性会变差。另一方面，0.05 M ZTO背沟道TFT的电学性能比0.1 M ZTO背沟道TFT差。这与沟道层厚度薄导致的背沟道效应有关。在这些器件中，0.1 M ZTO背沟道TFT具有最低的总陷阱密度、出色的电学性能和稳定性。因此，我们推荐IZO/ZTO（0.1 M）TFT作为一种有前景的沟道结构用于先进显示应用。
