吳育任臺灣大學:光電工程學研究所黃智怡Huang, Chih-IChih-IHuang2010-07-012018-07-052010-07-012018-07-052009U0001-0308200921465600http://ntur.lib.ntu.edu.tw//handle/246246/188457近年來，由於透明電極和薄膜電晶體在光照和顯示技術上的應，關於透明電極和薄膜電晶體的研究變得越來越重要，因此，如製造高電子遷移率的透明電極和薄膜電晶體成為業界關注的問。在本論文中，我們利用蒙地卡羅的方法分析多晶格的氧化鋅鎂氧化鋅薄膜層的電子遷移率，我們的研究考慮了晶格界面散射、離雜質散射、聲子散射和合金散射對於的影響，我們利用二維帕和漂移擴散方程來計算晶格界面強度、晶粒大小和屏蔽效應對電遷移率的影響。此外，我們也提出了氧化鋅鎂薄膜層的臨界厚，透過適當的設計，我們可以利用調變摻雜的技術和自發及壓電化，降低晶界強度，並提高氧化鋅薄膜層的電子遷移率。The study of transparent conducting oxide (TCO) and thin film transistor (TFT) has become an important area due to the applications of lighting and display technology. Therefore, finding a high mobility and conductivity TCO materials would be a key issue to the industry. In this paper, we have applied the Monte Carlo method to analyze the mobility of single and poly-crystalline MgZnO/ZnO thin film layer. The effects of grain boundary scattering, ionized impurity scattering, phonon scattering as well as alloy scattering have been included in our program. The grain boundary potential, the grain boundary size and carrier screening effect has been analyzed with our developed 2D Poisson and drift-diffusion solver. The critical depth of the MgZnO layer is also presented in our study. With a careful design of modulation doping and including the effect of spontaneous and piezoelectric polarization, the grain boundary potential can be suppressed and thus the mobility of the ZnO layer can be improved.口試委員會審查表. . . . . . . . . . . . . . . . . . . . . . . . . i謝. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii文摘要. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iv文摘要. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v錄. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vi目錄. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix目錄. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xiv Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.1 Thin film transistor . . . . . . . . . . . . . . . . . . . . 1.2 Introduction to ZnO and MgxZn1−xO alloy . . . . . . . 2.3 Grain boundary . . . . . . . . . . . . . . . . . . . . . . 5.3.1 Screening effect . . . . . . . . . . . . . . . . . . 5.3.2 Polarization effect . . . . . . . . . . . . . . . . . 6.4 Motivation . . . . . . . . . . . . . . . . . . . . . . . . . 8 Formalism . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.1 2D Poisson and drift-diffusion solver . . . . . . . . . . 10.2 Monte Carlo method and the scattering mechanisms . . 15.2.1 Monte Carlo method . . . . . . . . . . . . . . . 15.2.2 Ionized impurity scattering . . . . . . . . . . . . 19.2.3 Grain boundary scattering . . . . . . . . . . . . 21.2.4 Other scattering mechanisms . . . . . . . . . . 24 Device Design Issues . . . . . . . . . . . . . . . . . . . . . . 28.1 The Influence of the grain boundary potential and grainoundary size . . . . . . . . . . . . . . . . . . . . . . . 28.2 Modulation doping . . . . . . . . . . . . . . . . . . . . 31.2.1 The grain boundary potential . . . . . . . . . . 32.2.2 Carrier distribution . . . . . . . . . . . . . . . . 34.3 The influence of different Mg composition . . . . . . . 35.3.1 The grain boundary potential . . . . . . . . . . 36.3.2 Carrier distribution . . . . . . . . . . . . . . . . 39.4 The Influence of different trap widths . . . . . . . . . . 42.5 The influence of different depth of the MgZnO layer . . 45.5.1 The critical depth of the MgZnO layter dependsn different polarization charge . . . . . . . . . 48 Studies of the Carrier Mobility . . . . . . . . . . . . . . . . . 53.1 The influence of polarization charge . . . . . . . . . . . 53.2 The influence of different Mg composition and trap width 55.3 The average electron mobility of MgZnO/ZnO multilayer. 59.4 The velocity versus electric field curve. . . . . . . . . . 62 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . 64eference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 662338362 bytesapplication/pdfen-US氧化鋅鎂/氧化鋅異質結構蒙地卡羅壓電極化晶格界面遷移率MgZnOZnOheterostructureMonte Carlo Methodpiezoelectric polarizationgrain boundarymobilitythesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/188457/1/ntu-98-R96941068-1.pdf