Low Voltage Indium-Oxide-Zinc Thin Film Transistor Gated by KH550 Solid Electrolyte

Abstract

With the development of integrate circuit and artificial intelligence, many kinds of transistors have been invented. In recent years, wide attention has been paid to the oxide thin film transistors due to its ease preparation, low cost, and suitability for mass production. Traditionally used gate dielectric film (such as silicon dioxide film) in oxide thin film transistor owns low dielectric constant, which leads to weak capacitive coupling between the gate dielectric layer and the channel layer. As a result, high voltage (10 V or more) needs to be applied on the gate electrode in order to achieve the purpose of regulating the current of channel layer. Therefore, new oxide thin film needs to be developed. In this work, silane coupling agents (3-triethoxysilypropyla-mine) KH550 solid electrolyte film was obtained by spin coating-process. The KH550 solid electrolyte was used as gate dielectric layer to fabricate low-voltage indium zinc oxide thin film transistor. The surface topography and thickness of KH550 solid electrolyte film were characterized by atomic force microscope and field emission scanning electron microscope, respectively. The capacitance-frequency curve of the sample was measured by impedance analyzer (Soloartron 1260A), and the electrical characteristics of the sample were analyzed by a semiconductor parameter analyzer (Keithley 4200 SCS). A maximum specific capacitance of about 7.3 µF/cm² is obtained at 1 Hz. The transistor shows a good stability of pulse operation and negative bias voltage, the operation voltage is only 2 V, the current on/off ratio is about 1.24 × 10⁶, and the subthreshold swing is 169.2 mV/dec. The development of KH550 solid electrolyte gate dielectric provides a novel way for the research of oxide thin film transistor.

摘要

随着集成电路和人工智能的发展，发明了各种各样的晶体管。近年来，氧化薄膜晶体管因其易于制备、成本低、适合批量生产而受到广泛关注。氧化物薄膜晶体管中传统使用的栅介质膜(如二氧化硅膜)介电常数较低，导致栅介质层与沟道层之间的电容耦合较弱。为了达到调节沟道层电流的目的，需要在栅电极上施加高电压(10 V或更高)，因此需要开发新型氧化物薄膜。采用旋涂法在氧化铟锡玻璃表面制备了硅烷偶联剂（γ-氨丙基三乙氧基硅烷）KH550固态电解质薄膜，以此为栅介质制备了氧化铟锌薄膜晶体管。利用原子力显微镜和扫描电子显微镜对KH550薄膜的表面形貌和厚度进行表征；使用阻抗分析仪测试了样品的电容-频率曲线；通过半导体参数仪分析了器件的电学特性。结果表明，频率为1 Hz时的单位面积电容达7.3 µF/cm²，晶体管的工作电压为2 V、开关比1.24×10⁶、亚阈值摆幅169.2 mV/dec、场效应迁移率2.1 cm²/(V·s)，其脉冲工作稳定性和负偏压稳定性良好。KH550固态栅介质的开发研究为氧化物薄膜晶体管栅介质的研究提供了一种新的方向和思路。