The higher mobility is needed for thin film transistor (TFT) mainly used to be applied in the larger size flat-panel displays (FPDs). The amorphous metal oxide TFT has mobility higher than 10 cm2/V¡Es and can substitute the poor mobility (<1 cm2/V¡Es) of traditional amorphous silicon TFT, which shows a great potential for the next generation. Due to the superior characteristics in amorphous metal oxide TFT, therefore, the amorphous metal oxide TFT has been studied extensively. Usually, the source/drain with island type device has a large overlapped/contact area that we cannot determine the exact electron path. That the sample of inverted stagger £\-IGZO TFTs with via type device has smaller contact area and can be estimated the electron path. In this thesis, the devices with different M1 overlaps etching stop layer (ESL) via distance, M2 £\-IGZO contact size and the fringe field effect are investigated. Although the characteristics of £\-IGZO TFTs have great performance, the electrical stability under illumination and long term bias stress are still a important issue to study before implement them into display. Thus, the devices with different structures that we mentioned previously are investigated the electrical reliability which are the negative bias stress of gate voltage, hot carrier stress effect and negative bias of illumination. The electron path of via type is extracted by contact resistance which is greater than the distance between S/D via. Experiment results show that the increased offset between M1 and ESL via generates the resistance-liked effect in electrical characteristics. The hot carrier stress effect is independent of M2 £\-IGZO contact size in short channel length devices and there are close depletion lengths in drain side. The negative bias stress of illumination is proceeded in the fringe field effect devices, which results a negative shift of threshold voltage due to the hole trapping.

Abstract With the critical development trend of industry of the world, TFT-LCD industry, following the footstep of semi-conductive industry, has become an important leading industry of Taiwan to the economic policy of the Government. The ¡§Two Trillion Double Star¡¨plan pro- -moted by Industrial Development Bureau fo Taiwan intends to push up the production values of the two industries, semi-conductive and flat panel photonic displayer, to exceed NT$ 1 trillion respectively in 2006. This plan also promotes digital contents and biotechnical industry to be two star industries with high potentials of development. Therefore, TFT- LCD industry is undoubtedly the core industry of the next wave of econo- mic growth in Taiwan. According to the distinguishing characteristics of capital and technology density, short-lived productive cycle, and variable productive technique in TFT-LCD industry, cash flow out of investment activities became the key point to promote the competitiveness with the continuously overcharge in the next generation panel field.In addition, the investors would find that the TFT-LCD panel factories have no ability to support the cash flow out which invested in equipment if they do not ask for finance. In this paper, we attempt to investigate the relationship between variation of cash flow in operation, investment, and finance activities and potential risk of operation in enterprise by financial statement in TFT-LCD industry. In addition, this dissertation commence with ROE and development from Du-Pont Formula. Our research decomposes ROE to fundamental elements in enterprise step by step, such as the construction of cost and expense and the risk of business. Furthermore, we afford a referable approach to estimate performance of companies by Du-Pont Formula. Key Words¡G Thin Film Transistor (TFT), Liquid Crystal Display (LCD),Cash Flow, Risk, Risk Management, Du Pont Equation, Du Pont Ratio.

Thin Film Transistors (TFTs) are widely used in large area electronics because they offer the advantage of low cost fabrication and wide substrate choice. TFTs have been conventionally used for switching applications in large area display arrays. But when it comes to designing a sensor actuator system on a flexible substrate comprising entirely of organic and inorganic TFTs, there are two main challenges – i) Fabrication of complementary TFT devices is difficult ii) TFTs have a drift in their threshold voltage (VT) on application of gate bias. Also currently there are no circuit simulators in the market which account for the effect of VT drift with time in TFT circuits. The first part of this thesis focuses on integrating the VT shift model in the commercially available AIM-Spice circuit simulator. This provides a new and powerful tool that would predict the effect of VT shift on nodal voltages and currents in circuits and also on parameters like small signal gain, bandwidth, hysteresis etc. Since the existing amorphous silicon TFT models (level 11 and level 15) of AIM-Spice are copyright protected, the open source BSIM4V4 model for the purpose of demonstration is used. The simulator is discussed in detail and an algorithm for integration is provided which is then supported by the data from the simulation plots and experimental results for popular TFT configurations. The second part of the thesis illustrates the idea of using negative feedback achieved via contact resistance modulation to minimize the effect of VT shift in the drain current of the TFT. Analytical expressions are derived for the exact value of resistance needed to compensate for the VT shift entirely. Circuit to realize this resistance using TFTs is also provided. All these are experimentally verified using fabricated organic P-type Copper Phthalocyanine (CuPc) and inorganic N-type Tin doped Zinc Oxide (ZTO) TFTs. The third part of the thesis focuses on building a robust amplifier using these TFTs which has time invariant DC voltage level and small signal gain at the output. A differential amplifier using ZTO TFTs has been built and is shown to fit all these criteria. Ideas on vertical routing in an actual sensor actuator interface using this amplifier have also been discussed such that the whole system may be “tearable” in any contour. Such a sensor actuator interface can have varied applications including wrap around thermometers and X-ray machines.