Homojunction structure amorphous oxide thin film transistors with ultra-high mobility
Rongkai Lu, Siqin Li, Jianguo Lü, Bojing Lu, Ruqi Yang, Yangdan Lu, Wenyi Shao, Yi Zhao, Liping Zhu, Fei Zhuge, Zhizhen Ye
Abstract
Abstract Amorphous oxide semiconductors (AOS) have unique advantages in transparent and flexible thin film transistors (TFTs) applications, compared to low-temperature polycrystalline-Si (LTPS). However, intrinsic AOS TFTs are difficult to obtain field-effect mobility ( μ FE ) higher than LTPS (100 cm 2 /(V·s)). Here, we design ZnAlSnO (ZATO) homojunction structure TFTs to obtain μ FE = 113.8 cm 2 /(V·s). The device demonstrates optimized comprehensive electrical properties with an off-current of about 1.5 × 10 –11 A, a threshold voltage of –1.71 V, and a subthreshold swing of 0.372 V/dec. There are two kinds of gradient coupled in the homojunction active layer, which are micro-crystallization and carrier suppressor concentration gradient distribution so that the device can reduce off-current and shift the threshold voltage positively while maintaining high field-effect mobility. Our research in the homojunction active layer points to a promising direction for obtaining excellent-performance AOS TFTs.