【作者】 王丽杰；

【导师】 张彤；

【作者基本信息】 吉林大学 ， 微电子学与固体电子学， 2010， 博士

【摘要】 本论文围绕用于OLED显示驱动薄膜晶体管开展了系列研究,工作主要包含两大部分内容:其一是关于薄膜晶体管的设计与制作部分,其二是关于AM-OLED显示驱动的薄膜晶体管阵列电路的设计部分。薄膜晶体管的设计与制作部分主要工作包括:1.制作了基于水热合成的Na2Ti3O7纳米线晶体管,器件结构为ITO/PMMA-GMA/Al/ Na2Ti3O7纳米线。该器件呈现P型特性,场效应迁移率μ=0.1 cm2/Vs,开关电流比可以达到103。2.制作了顶栅自对准结构的CuPc薄膜晶体管器件,器件结构为CuPc/nylon/CaF2/MoO3/Al,该器件呈现P型特性,场效应迁移率μ=2.68 cm2/Vs,开关电流比可以达到104。3.制作了聚噻吩纳米纤维的晶体管。器件结构为噻吩纳米纤维/Au/相对干燥的空气与SiNx复合绝缘介质/重掺杂的Si栅电极。该器件显示出P型特性,开关电流比可以达到0.4×106,开启电压约为1 V,场效应迁移率μ= 14.9 cm2/Vs。电路设计部分主要工作包括:1.设计了一种多栅双沟道P-Si TFT结构,这种结构P-Si TFT的关态漏电流与同样工艺条件下多栅TFT在同一个数量级,开态电流增加一倍,这就使得宽长比相同的TFT的驱动负载能力增大了,提供同样电流的情况下在集成矩阵当中占更小的面积,有效地提高开口率。2.设计了用于AM-OLED的多晶硅像素驱动电路,该像素电路包含3个TFT,用该电路实现TFT驱动阵列制备的过程中,可以省去一次掩模掺杂的过程。3.设计了一种LTPS-TFT-AMOLED显示区制备OLED阵列后,显示区TFT与OLED阵列的综合测试发光像素工作状态的测试方法,在显示区外围增加适量的晶体管便可达到测试目的,而且可以无需外接驱动芯片就可以点亮整个显示屏。更多还原

【Abstract】 Organic transistors have attracted considerable interest because they are lightweight, flexible, inexpensive, and highly efficient over large areas. As a result of these characteristics, organic transistors are expected to find use in a variety of applications, including electronic barcodes, displays, and sensors. Until now, their performance has been inferior to inorganic transistors because of their lower mobility values (typical mobility ranges are 1–10 and 500–10000 cm2/Vs for organic and inorganic semiconductors, respectively). Attempts to enhance the performance of organic transistors have relied on designing new type of device structures. In addition, increasing attention has been paid to nano- or microstructured materials during past decades because of their intriguing optical and electronic properties. Of particular interest in this regard is one-dimensional (1D) organic nano- or microstructures on various substrates with high length/diameter aspect ratio, since such highly ordered functional materials are potential candidates as active components in a wide range of research field including gas sensors, organic light-emitting diodes (OLED), organic field effect transistors (OFET), optical waveguide fibers, photodetectors, and solar cells, etc. The quantum size effect of micro- and nano-structured semiconductors could induce novel optical and electronic properties when compared with those of thin-film transistor materials. The 1D alignment facilitate carrier transport hence improve the charge mobility of the electronic devices, however, the on/off current ratio (Ion/Ioff) of the 1D semiconductor is commonly lower than that of thin-film transistors. To fabricate integrated optoelectronic devices, it is important to control the assembly and alignment of the nano- or microwires in desired position on the substrate. Thus, the development of efficient self-assembly approach is highly important toward unique 1D micro- or nanostructured materials for semiconducting transistors.In this thesis, we reported two strategies, (a) designing novel device structure and (b) constructing ordered 1D nano- semiconducting materials, for high performance field effect transistors. Our approach to resolving first issue is to employ a self-aligned type transistor for organic semiconducting materials which usually employed in inorganic thin-film transistors. As for the second issue, A simple electronspun approach allows us controllably synthesize large quantities of well-defined 1D ultralong nanofibers. Field effect transistor devices based on the 1D fibers fabricated in situ on SiO2 substrate exhibited excellent semiconducting properties.1. Na2Ti3O7 nanowires with diameters of about 80–130 nm and lengths up to several tens of micrometers are synthesized via a simple hydrothermal method and characterized by the field-emission scanning electron microscopy and X-ray diffraction. Back-gate field-effect transistors based on these nanowires are fabricated on indium tin oxide glass substrates with polymethyl-methacrylate-co-glyciclyl-methacrylate as the gate insulator layers. Typical p-type semiconductor material properties are observed in our investigations. The field-effect mobility is about 0.1 cm2/Vs. The capacitance per unit area of the dielectric is 3.43 nF/cm2 (dielectric constant, k = 3.9). The on/off ratio is around 103.2. For the first time, we tried to apply the self-aligned device structure to organic thin film transistors. This type of device fabrication has the following two advantages: firstly, a top-gate top-contact self-aligned field effect transistor can be constructed by three-time vacuum evaporations, significantly simplifying the device fabrication process. Secondly, the transistor fabricated by this method exhibits excellent conducting properties. The mobility achieved 2.68 cm2/Vs and Ion/Ioff of the transistor achieved about 104, demonstrating its potential for practical application.3. Electrospining has received steadily increasing interest due to its ability to produce nanometer-sized fibers with a high level of reinforcement. A large number of polymers have been electrospun into nanofiber with fiber diameters typically ranging from 50 to 500 nm. Considering this point, we employed this methodology to fabricate polythiophene nanofiber based transistors in the present study. In this method, the electro-spun polymer PAN (polyacrylonitrile) are used as the template and conducting polythiophene are then coated on the surface of the core PAN fibers by in-situ deposition polymerization. The polythiophene nanofiber prepared by this method can be directly deposited on glass substrates pre-coated by Si insulator with highly ordered alignment. Then source-drain electrodes (Au) were evaporated through shadow masks. This device exhibits typical p-type semiconducting properties. The transistor reached maxima Ion/Ioff of about 0.4×106. The calculated mobility is 14.9 cm2/Vs; this value is even higher than the mobility of P3HT.4. Firstly, a multi-gate double-channel Poly-Si TFT structure has proposed. Open-state current of the transistor double than multi-gate single-channel Poly-Si TFT transistor; Only P-channel 3T pixel drive circuit for AM-OLED has designed and simulated with Hspice software. The 3T pixel circuit has simplified the process. The pixel circuit design has certain advantages and advanced; At last, a LTPS-TFT-AMOLED test method has invented.更多还原