基于低频噪声的有机场效应晶体管可靠性研究

OFET has potential to be applied widely such as flexible displays, but device reliability becomes a bottleneck for commercial application. Organic devices are advantageous in low frequency field, so low frequency noise can’t be neglected in practice. The mechanism of carrier transportation in OFETs remains unclear. Low frequency noise of semiconductor devices closely relates to device reliability, carrier transportation and traps around interface. It indicates internal information of a device as well as influencing its performance. The project will concentrate on 1/f noise and RTS noise of OFETs. Mechanism of low frequency noise in OFETs will be researched. The relation among low frequency noise, carrier transportation, trap distribution, and device reliability will be studied. By means of low frequency noise, distribution of position and energy of traps around interface will be investigated. Based on low frequency noise, reliability of OFETs will be studied. Change of distribution of position and energy of traps due to reliability testing will be analyzed, and the reason will be examined. The origin of threshold voltage shift and transconductance degradation will be explored from a microscopic perspective by low frequency noise and other tools to characterize surface and interface. After completion of the project, mechanism of low frequency noise in OFETs will be clarified. Connection between device reliability and distribution of traps around interface will be unveiled. Understanding of carrier transportation in OFETs will be deepened. Last but not least, low frequency noise being applied to characterize reliability of organic semiconductor devices may become feasible.

OFET在柔性显示等领域前景广阔，但可靠性问题是制约其规模应用的重要瓶颈。有机器件的优势在于低频领域，低频噪声在应用中难以忽视。OFET的载流子输运机理还未被完全认识。器件的低频噪声与可靠性、载流子输运、界面陷阱密切相关，影响器件性能，也间接反映其内部信息。本项目将对OFET的1/f噪声和RTS噪声进行研究。研究上述低频噪声的机理，以及低频噪声与载流子输运、界面陷阱分布和器件可靠性的内在联系。通过低频噪声研究界面附近陷阱的空间和能量分布。基于低频噪声研究OFET的可靠性，分析可靠性试验前后界面附近陷阱的空间和能量分布的变化及其机理。通过低频噪声并辅以其它的表面、界面表征手段，从微观上揭示阈值电压漂移，跨导退化等问题的本质。本项目的完成将阐明OFET低频噪声的机理，揭示界面陷阱分布与OFET器件可靠性的内在联系，深化对OFET载流子输运的理解，探索基于低频噪声研究有机器件可靠性问题的可行性。

有机场效应晶体管在柔性显示等领域前景广阔，但可靠性问题是制约其规模应用的重要瓶颈。有机器件的优势在于低频领域，低频噪声在应用中难以忽视。OFET的载流子输运机理还未被完全认识。器件的低频噪声与可靠性、载流子输运、界面陷阱密切相关，影响器件性能，也间接反映其内部信息。. 研究工作一直围绕着有机场效应晶体管的制备工艺，低频噪声的探测与分析，以及器件可靠性这一研究目标进行逐步地展开。成功制备出了以分别以铪基氧化物、SiO2为栅介质，并五苯或P3HT为半导体的有机场效应晶体管。通过输出特性曲线和转移特性曲线测试，证实上述器件表现出了良好的场效应特性。研究了抗外界干扰的电磁屏蔽技术，以及微弱电信号的检测技术。成功获得了有机场效应晶体管的噪声功率谱，通过频谱分析，确认该噪声功率谱属于低频噪声类的1/f噪声。证实上述测试和分析方法可获得有机场效应晶体管的稳定的、可重复的1/f噪声功率谱分布。研究了偏压应力、光照等对有机场效应晶体管的可靠性的影响。发现偏压应力会使得器件的1/f噪声功率谱发生漂移，间接证实了阈值电压漂移、跨导退化、1/f噪声功率谱漂移之间的内在联系，即器件内部的陷阱是导致上述三种现象的重要因素。. 拓展了有机场效应晶体管的研究，考虑到二维过渡金属硫化物场效应晶体管（transition metal dichalcogenides （TMD） FET）与有机场效应晶体管具有较高的相似性，且TMD FET与有机场效应晶体管的结合具有潜在的应用价值，我们利用有机场效应晶体管的研究经验对TMD FET开展了研究。基于半导体器件物理，利用电荷控制方法，分别提出了TMD FET的显式I-V模型，以及双极型过渡金属硫化物场效应晶体管（Ambipolar TMD FET）的紧缩型I-V特性模型。对于半导体器件特性预测分析和集成电路设计都具有价值。. 本项目的完成将深化对OFET低频噪声的机理，揭示界面陷阱分布与OFET器件可靠性的内在联系，深化对OFET载流子输运的理解，探索基于低频噪声研究有机器件可靠性问题的可行性。