Heo Jae Sang, Choi Seungbeom, Jo Jeong-Wan, Kang Jingu, Park Ho-Hyun, Kim Yong-Hoon, Park Sung Kyu
School of Electrical and Electronic Engineering, Chung-Ang University, Seoul 06980, Korea.
SKKU Advanced Institute of Nanotechnology (SAINT) and School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon 16419, Korea.
Materials (Basel). 2017 Jun 3;10(6):612. doi: 10.3390/ma10060612.
In this paper, we demonstrate high mobility solution-processed metal-oxide thin-film transistors (TFTs) by using a high-frequency-stable ionic-type hybrid gate dielectric (HGD). The HGD gate dielectric, a blend of sol-gel aluminum oxide (AlO) and poly(4-vinylphenol) (PVP), exhibited high dielectric constant (ε~8.15) and high-frequency-stable characteristics (1 MHz). Using the ionic-type HGD as a gate dielectric layer, an minimal electron-double-layer (EDL) can be formed at the gate dielectric/InO interface, enhancing the field-effect mobility of the TFTs. Particularly, using the ionic-type HGD gate dielectrics annealed at 350 °C, InO TFTs having an average field-effect mobility of 16.1 cm²/Vs were achieved (maximum mobility of 24 cm²/Vs). Furthermore, the ionic-type HGD gate dielectrics can be processed at a low temperature of 150 °C, which may enable their applications in low-thermal-budget plastic and elastomeric substrates. In addition, we systematically studied the operational stability of the InO TFTs using the HGD gate dielectric, and it was observed that the HGD gate dielectric effectively suppressed the negative threshold voltage shift during the negative-illumination-bias stress possibly owing to the recombination of hole carriers injected in the gate dielectric with the negatively charged ionic species in the HGD gate dielectric.
在本文中，我们通过使用高频稳定的离子型混合栅极电介质（HGD）展示了高迁移率的溶液处理金属氧化物薄膜晶体管（TFT）。HGD栅极电介质是溶胶 - 凝胶氧化铝（AlO）和聚（4 - 乙烯基苯酚）（PVP）的混合物，表现出高介电常数（ε~8.15）和高频稳定特性（1 MHz）。使用离子型HGD作为栅极介电层，可以在栅极电介质/InO界面形成最小电子双层（EDL），提高TFT的场效应迁移率。特别是，使用在350°C退火的离子型HGD栅极电介质，实现了平均场效应迁移率为16.1 cm²/Vs的InO TFT（最大迁移率为24 cm²/Vs）。此外，离子型HGD栅极电介质可以在150°C的低温下进行处理，这可能使其能够应用于低热预算的塑料和弹性体基板。此外，我们系统地研究了使用HGD栅极电介质的InO TFT的操作稳定性，并且观察到HGD栅极电介质有效地抑制了负光照偏置应力期间的负阈值电压偏移，这可能是由于注入到栅极电介质中的空穴载流子与HGD栅极电介质中带负电荷的离子物种复合所致。
