近十年來，有機薄膜電晶體已有顯著的發展且現在很有可能應用在許多地方。與矽為基礎的無機薄膜電晶體比較，有機薄膜電晶體在製作及應用上，基本提供兩個主要的優點:低溫需求及低成本，而低溫製程其中一個考量的重要因素，就是如何在低溫下成長出閘極絕緣層，這是一項嚴峻的挑戰。
在我們的研究中，利用中空陰極化學氣相沉積低溫二氧化矽薄膜在重摻雜的矽基板上，當作有機薄膜電晶體的閘極絕緣層。雖然這層二氧化矽與高密度電將輔助化學氣相沉積相比，顯現較差的絕緣特性，使得薄膜電晶體的關閉電流(Ioff)上升，但他表面平坦且顯示疏水的性質，因此利用中空陰極化學氣相沉積二氧化矽薄膜上的五苯環(pentacene)晶粒大小會比在高密度電將輔助化學氣相沉積的晶粒來的大，這個現象導致中空陰極化學氣相沉積低溫二氧化矽的有機薄膜電晶體會有高的導通電流及載子移動率，因此我們的研究證明了80 ℃成長的二氧化矽不僅能用在有機薄膜電晶體上且還能提供優越的電晶體特性。
並且本實驗研究在不同量測環境下，對有機薄膜電晶體電性的影響，透過表面物性(AFM)及薄膜吸收光譜(FTIR)的分析，可以發現水氣確實蘊藏於pentacene內且造成劣化的主要原因，因此證明了水氣的含量對元件電性的重要。

Organic thin film transistors (OTFTs) have made impressive progress over the past decades, and it is now likely that OTFTs will find their applications in a number of ways. OTFTs basically provide two principal advantages over Si-based TFTs in processes and application: low thermal budget and low cost. One important factor for low temperature process may be how to fabricate a gate dielectric film at a low temperature. This is a difficult challenge.
We report on the fabrication of pentacene thin-film transistors (TFTs) with SiO2 films as the gate dielectric that has been deposited on a heavily doped Si-wafer by Hollow Cathode CVD at low temperature. Although the SiO2 was expected to show lower insulating properties than HDP-CVD SiO2, the surface properties exhibited smooth and a hydrophobic character. Therefore, the pentacene grain size on Hollow Cathode CVD SiO2 is much larger than HDP-CVD SiO2. Based on these arguments, it may result in OTFT using low-temperature hollow cathode CVD SiO2 with higher field mobility and on current. Our work demonstrates that 80 ℃-deposited SiO2 is not only promising gate dielectric material for organic TFTs, but also providing good transistors characteristic.
We also investigated the influence of the influence of different measuring environment on the electrical characteristics of pentacene-based thin film transistors. Through surface morphology analysis by atomic force microscopy (AFM) and absorption analysis by infrared (IR) spectroscopy, it was found that the adsorption of H2O on the pentacene layer was the main reason for the degradation. Therefore, we have demonstrated the number of the moisture is a important factor on the electrical characteristics of pentacene-based thin film transistors.

[1] Taeksoo Ji, Jining Xie, and Vijay K. Varadan, “Design of Pentacene Thin Film Transistors On Flexible Substrates” Proc. of SPIE Vol. 5763, 77-83

[2] Sung Kyu Park, Yong Hoon Kim, Jeong In Han, Dae Gyu Moon, and Won Keun Kim, “High-Performance Polymer TFTs Printed on a Plastic Substrate” IEEE Trans. Electron Devices, 49 (2002) 2008-2015

[3] Sang Chul Lim, Seong Hyun Kim, Jung Hun Lee, Mi Kyung Kim, Do Jin Kim, Taehyoung Zyung “Surface-treatment effects on organic thin-film transistors” Synthetic Metals 148 (2005) 75–79

[4] Dong Guo , Shiro Entani, Susumu Ikeda, Koichiro Saiki “Effect of UV/ozone treatment of the dielectric layer on the device performance of pentacene thin film transistors” Chemical Physics Letters 429 (2006) 124–128

[5] Seung Hoon Han, Jun Hee Kim, Jin Jang, Sang Mi Cho, Myung Hwan Oh, Sun Hee Lee and Dong Joon Choo,”Lifetime of organic thin-film transistors with organic passivation layers” Appl. Phys. Lett. 88, 073519 (2006)

[6] C. J. Drury, C. M. J. Mutsaers, C. M. Hart, M. Matters, and D. M. de Leeuw, Appl. Phys. Lett. 73, 108 (1998)

[7] M. Halik, H. Klauk, U. Zschieschang, T. Kriem, G. Schmid, W. Radlik, and K. Wussow, Appl. Phys. Lett. 81, 289 (2002)

[8] H. E. Katz, X. M. Hong, A. Dodabalapur, and R. Sarpeshkar, J. Appl. Phys. 91, 1572 (2002)

[9] A.Tsumura, H. Koezuka, T. Ando, Appl. Phys. Lett. 1986, 49, 1210

[10]A. Assadi, C. Svensson, M. Willander, O. Ingans, Appl. Phys. Lett.1988

[11] J. Paloheimo, E. Punkka, H. Stubb, P.Kuivalainen, in Lower Dimensional Systems and Molecular Devices, Proceedings of NATO ASI, Spetses, Greece (Ed: R. M. Mertzger), Plenum, New York 1989

[12] Z. Bao, A. Dodabalapur, A. J. Lovinger, Appl. Phys. Lett., 1996, 69, 4108

[13] H. Sirringhaus, N. Tessler, R. H. Friend, Science 1998,280,1741

[14] F. Ebisawa, T. Kurokawa, S. Nara, J. Appl. Phys. 1983, 54, 3255

[15] J. H. Burroughes, C. A. Jones, R. H. Friend, Nature 1988, 335, 137

[16] H. Fuchigami, A. Tsumura, H. Koezuka, Appl. Phys. Lett. 1993, 63, 1372

[17] F. Garnier, A. Yassar, R. Hajlaoui, G. Horowitz, F. Deloffre, B. Servet, S. Ries, P. Alnot, J. Am. Chem. Soc. 1993, 115, 8716

[18] B.Servet, G. Horowitz, S. Ries, O. Lagorsse, P. Alnot, A. Yassar, F. Deloffre, P. Srivastava, R. Hajlaoui, P. Lang, F. Garnier, Chem. Mater. 1994, 6, 1809

[19] A. Dodabalapur, L. Torsi, H. E. Katz, Science 1995, 268, 270. L. Torsi, A. Dodabalapur, A. J. Lovinger, H. E. Katz, R. Ruel, D. D. Davis, K. W. Baldwin, Chem. Mater. 1995, 7, 2247

[20] C. D. Dimitrakopoulos, B. K. Furman, F. Graham, S. Hegde, S. Purushothaman, Synth. Met. 1998, 2

[21] H. E. Katz, L. Torsi, A. Dodabalapur, Chem. Mater. 1995, 7, 2235

[22] R. Hajlaoui, D. Fichou, G. Horowitz, B. Nessakh, M. Constant, F. Garnier, Adv. Mater. 1997, 9, 557

[23] R. Hajlaoui, G. Horowitz, F. Garnier, A. Arce-Brouchet, L. Laigre, A. Elkassmi, F. Demanze, F. Kouki, Adv. Mater. 1997, 9, 389

[24] J. H. Sch^n, C. Kloc, B. Batlogg, Org. Electron. 2000, 1, 57

[25] Y. -Y. Lin, D. J. Gundlach, S. Nelson, T. N. Lett. 1997, 18, 606. Jackson, IEEE Electron Device.

[26] C. D. Dimitrakopoulos, A. R. Brown, A. Pomp, J. Appl. Phys. 1996, 80, 2501

[27] Y. Y. Lin, D. J. Gundlach, T. N. Jackson, 54th Annual Device Research Conference Digest 1996, p.80. 1991, 58, 1500

[28] G. Horowitz, X. Peng, D. Fichou, F. Garnier, Synth. Met. 1992, 51, 419

[29] R. C. Haddon, A. S. Perel, R. C. Morris, T. T. M. Palstra, A. F. Hebard, R. M. Fleming, Appl. Phys. Lett. 1995, 67, 121

[30] J. Kastner, J. Paloheimo, H. Kuzmany, in Solid State Sciences(Eds:H. Huzmany, M. Mehring, J. Fink), Springer, New York 1993, pp. 515-521

[31] G. Guillaud, M. Al Sadound, M. Maitrot, Chem. Phys. Lett. 1990, 167,503.

[32] Z. Bao, A. J. Lovinger, J. Brown, J. Am. Chem. Soc. 1998, 120, 207.

[33] H. Fuchigami, A. Tsumura, H. Koezuka, Appl. Phys. Lett. 1993, 63, 1372.

[34] A. R. Brown, D. M. de Leeuw, E. J. Lous, E. E. Havinga, Synth. Met. 1994, 66, 257.

[35] J. G. Laquindanum, H. E. Katz, A. Dodabalapur, A. J. Lovinger, J. Am. Chem. Soc. 1996, 118, 11 331.

[36] C. D. Dimitrakopoulos, and P. R. L. Malenfant Adv. Mater., 14, 99 (2002)

[37] M. Baldo, M. Deutsch, P. Burrows, H. Gossenberger, M. Gerstenberg, V. Ban, and S.Forrest, “Organic Vapor Phase Deposition” Adv. Mater. vol.10, no.18, pp.234-238, 1998.

[38]E. M. Conwell, “Impurity Band Conduction in Germanium and Slilcon,” Phys. Rev. 103, 51 (1956).

[39]N. F. Mott, Canadian J. Phys. 34, 1356 (1956).

[40]P. G. Le Comber, and W. E. Spear, “Electronic Transport in Amorphous Silicon Films,” Phys. Rev. Lett. 25, 509 (1970).

[41]S. M. Sze, Physics of Semiconductor Devices, Wiley, New York, 1981, CH. 7

[42]A. R. Brown, C. P. Jarrett, D. M. de Leeuw and M. Matters, “Field-eddect transistor made from solution-procceed organic semiconductors”, Synth. Met., vol. 88, pp. 37-55, 1997

[43]R. A. Street, D. Knipp, and A. R. Vo¨ lkel “Hole transport in polycrystalline pentacene transistors” Appl. Phys. Lett., Vol. 80, No. 9, 4 March 2002

[44] Roichman, Y., and Tessler, N., Appl. Phys. Lett. (2002) 80 (1), 151

[45] 黃正翰 “閘極絕緣層表面處理在低溫製程有機薄膜電晶體特性改善之研究” 台灣科技大學電子系碩士論文

[46]A. Tabata, N. Matsuno, Y. Suzuoki and T. Mizutani, “Optical properties and structure of SiO2 films prepared by ion-beam sputtering,” Thin Solid Films, 289, pp. 84-89, 1996.

[47] I. P. Lisovskii, V. G. Litovchenko, V. G. Lozinskii and G. I. Steblovskii, “IR spectroscopic investigation of SiO2 film structure”, Thin Solid Films, 213, pp. 164-169, 1992.

[48]Shashank C. Deshmukh and Eray S. Aydil “Low-temperature plasma enhanced chemical vapor deposition of SiO2” Appl. Phys. Lett., Vol. 65, No. 25, 19 December 1994

[49] Sang Chul Lima, Seong Hyun Kim, Jung Hun Lee, Mi Kyung Kim, Do Jin Kim, Taehyoung Zyung “Surface-treatment effects on organic thin-film transistors” Synthetic Metals 148 (2005) 75–79

[50] Kui-Xiang Ma, Chee-Hin Ho, Furong Zhu, Tai-Shung Chung, Thin Solid Films 371 (2000) 140.

[51] Wei-Yang Chou, Chia-Wei Kuo, Horng-Long Cheng, Yi-Ren Chen, Fu-Ching Tang, Feng-Yu Yang, Dun-Yin Shu, Chi-Chang Liao, App. Phys. Lett. 89 (2006) 112126.

[52] Sandra E. Fritz, Tommie Wilson Kelley, and C. Daniel Frisbie, “Effect of Dielectric Roughness on Performance of Pentacene TFTs and Restoration of Performance with a Polymeric Smoothing Layer” J. Phys. Chem. B 2005, 109, 10574-10577

[53] D. K. Hwang, Ji Hoon Park, Jiyoul Lee, Jeong-M. Choi, Jae Hoon Kim, Eugene Kim, and Seongil Im,“Improving Resistance to Gate Bias Stress in Pentacene TFTs with Optimally Cured Polymer Dielectric Layers” Journal of The Electrochemical Society, 153 (1) G23-G26 (2006)

[54] Y. F. Liew, H. Aziz, N. X. Hu, H. S. O. Chan, G. Xu. And Z. Popovic, Appl. Phys. Lett., 77, 2650 ( 2000 ).

[55] F. Papadimitrakopoulos, X. M. Zhang and K. A. Higginson, IEEE J. Sel. Top. Quantum Electron., 4, 49 ( 1998 ).

[56] 工研院-陳麒麟,張榮芳,張加強, “Flexible Display Development and Technology States”光電與半導體設備技術專輯

[57] L. Torsi, A. Dodabalapur, L. Sabbatini, P.G. Zambonin, Sens. Actuators, B 67 (2000) 312.

[58] T. Komoda, K. Kita, K. Kyuno, A. Toriumi, Jpn. J. Appl. Phys. 42 (2003) 3662.

[59] Seung Hoon Han, Jun Hee Kim, and Jin Jang, Sang Mi Cho and Myung Hwan Oh,Sun Hee Lee and Dong Joon Choo “Lifetime of organic thin-film transistors with organic passivation layers” App. Phys. Lett. 88 (2006) 073519.

[60] Zheng-Tao Zhu, Jeffrey T. Mason, Ru¨ diger Dieckmann, and George G. Malliaras “Humidity sensors based on pentacene thin-film transistors” App.Phys. Lett. 81 (2002) 4643