基于溶液法工艺的柔性透明双电层氧化物晶体管研究

Wideband oxide-based channel thin film transistors (TFTs) have attracted much attention for the applications of active-matrix displays and portable transparent electronics due to their high transparency, low-temperature process, and large mobilities. However, the usual approach for oxide deposition need the expensive vacuum-based equipments, and the traditional gate dielectric has weak control ability for the drain current, which results in a large operating voltage(>20V). Here, by using low-temperature solution-processed oxide as semiconductor and using electric-double-layer dielectric as gate insulator, we can construct low-temperature-processed（<200 oC）flexible transparent low-voltage(<2V) oxide thin-film transistors. Based on these devices, we can further develop dual-gate，vertical-channel, oxide-based two-dimensional-electronic-gas device structures to improve the transistor performance. Characterization methods like semiconductor parameter analyzer, scanning electron microscopy(SEM), transmission electron microscope(TEM), atomic force microscope (AFM) and X-ray diffraction(XRD) will be used to determine the device electrical performance and structure parameters of thin film, which can help us to further investigate the carrier-transport physics insights. It is of great importance to clarify relations between the device process and the key parameters such as carrier mobilities, subthreshold swing, on-to-off ratio, and channel/dielectric interface properties.

宽带隙氧化物薄膜晶体管由于其沟道材料具有可见光透明、低温成膜、高电子迁移率等优点，在有源矩阵显示、便携式透明电子器件等领域具有广阔的应用前景。但通常的氧化物制备需要真空溅射设备，工艺成本较高，传统的栅介质对电流的调控能力也较差，工作电压很大(>20V)。本申请项目拟采用低温溶液法工艺来制备氧化物半导体，利用双电层栅介质作为器件的栅绝缘层，制备出基于低温溶液法工艺（<200 oC）的柔性透明低电压（<2V)氧化物晶体管，达到降低工艺成本同时提高器件性能的目的。在此基础上，采用双栅、垂直沟道、氧化物二维电子气等独特的器件结构来进一步优化器件性能，并结合半导体参数分析仪和SEM、TEM、AFM、XRD等器件测试手段来研究器件的电学参数和薄膜结构特性，深入研究这类器件工作的载流子电学输运机制。探索器件的载流子迁移率、亚阈值斜率、电流开关比、栅介质/沟道界面特性等关键参数与器件工艺之间的内在关系。

宽带隙氧化物薄膜晶体管由于其沟道材料具有可见光透明、低温成膜、高电子迁移率等优点，在有源矩阵显示、便携式透明电子器件等领域具有广阔的应用前景。但通常的氧化物晶体管制备需要真空溅射设备，透明氧化物里面还有稀有金属（比如铟），工艺成本较高，传统的栅介质对电流的调控能力也较差，工作电压很大(>20V)。本项目中，我们基于低温溶液法工艺成功开发了几种双电层离子液聚合物栅介质（PVA、海藻酸钠、壳聚糖等），研制成功了共平面栅，双栅，垂直沟道等器件结构的低电压透明氧化物晶体管（工作电压小于2V、电流开关比大于10^4）。并成功开发了低成本的透明导电氧化物（Al-Zn-O）来取代传统的含铟透明氧化物ITO。利用半导体参数分析仪进一步详细表征和研究了器件的电学性能和内在的物理机制。此研究的成功开展为透明氧化物晶体管在新型的便携式透明电子器件的实际应用打下了坚实的基础。