Li Qi, Dong Junchen, Han Dedong, Xu Dengqin, Wang Jingyi, Wang Yi
Institute of Microelectronics, Peking University, Beijing 100871, China.
School of Information & Communication Engineering, Beijing Information Science and Technology University, Beijing 100101, China.
Nanomaterials (Basel). 2022 Mar 31;12(7):1167. doi: 10.3390/nano12071167.
Transparent conductive oxides (TCO) have been extensively investigated as channel materials for thin-film transistors (TFTs). In this study, highly transparent and conductive InSnO (ITO) and ZnO films were deposited, and their material properties were studied in detail. Meanwhile, we fabricated ZnO/ITO heterojunction TFTs, and explored the effects of channel structures on the hump characteristics of ZnO/ITO TFTs. We found that V-V was negatively correlated with the thickness of the bottom ZnO layer (10, 20, 30, and 40 nm), while it was positively correlated with the thickness of the top ITO layer (3, 5, 7, and 9 nm), where V is the gate voltage corresponding to the occurrence of the hump and V is the turn-on voltage. The results demonstrated that carrier transport forms dual current paths through both the ZnO and ITO layers, synthetically determining the hump characteristics of the ZnO/ITO TFTs. Notably, the hump was effectively eliminated by reducing the ITO thickness to no more than 5 nm. Furthermore, the hump characteristics of the ZnO/ITO TFTs under positive gate-bias stress (PBS) were examined. This work broadens the practical application of TCO and provides a promising method for solving the hump phenomenon of oxide TFTs.
透明导电氧化物（TCO）已被广泛研究用作薄膜晶体管（TFT）的沟道材料。在本研究中，沉积了高透明且导电的InSnO（ITO）和ZnO薄膜，并详细研究了它们的材料特性。同时，我们制备了ZnO/ITO异质结TFT，并探究了沟道结构对ZnO/ITO TFT驼峰特性的影响。我们发现V-V与底部ZnO层（10、20、30和40nm）的厚度呈负相关，而与顶部ITO层（3、5、7和9nm）的厚度呈正相关，其中V是对应驼峰出现的栅极电压，V是开启电压。结果表明，载流子传输通过ZnO和ITO层形成双电流路径，综合决定了ZnO/ITO TFT的驼峰特性。值得注意的是，通过将ITO厚度减小到不超过5nm，驼峰被有效消除。此外，还研究了正栅极偏置应力（PBS）下ZnO/ITO TFT的驼峰特性。这项工作拓宽了TCO的实际应用，并为解决氧化物TFT的驼峰现象提供了一种有前景的方法。
