石墨烯起源於在2004年，英國曼徹斯特大學的A. K. Geim和K. S. Novoselov利用機械剝離法(mechanical exfoliation)成功地將單層石墨從高定向熱裂解石墨(highly orientated pyrolytic graphite, HOPG)塊材上給剝離下來，引起了全世界的研究熱潮。由於石墨烯擁有許多優異的特性，因此亦是下一世代二維材料的候選人之一。

在現今資訊爆炸的時代，通訊科技的發達是不可或缺的因素之一。它拉近了人與人之間的距離，讓人們可以在第一時間內收到相關情報與訊息，不管是在軍事、交通、民間等方面上，都可見到通訊電子產品無所不在。近年來，因著石墨烯的高載子遷移率(200,000 cm^2/V‧s)、高電流承載力(> 10^9 A/cm^2)、高飽和速度及載子濃度易受閘極調變等優異特性，已經有許多石墨烯相關的高頻應用文獻被發表出來。雖然目前於碳化矽(SiC)基板上的石墨烯元件擁有極佳的高頻特性，但是製程成本十分昂貴，在量產上有實質的困難。

本論文選用同樣為絕緣性的氧化鋁(Al2O3)及氮化鋁(AlN)基板應用在石墨烯高頻元件上，並搭配T型鋁閘極結構與Self-alignment技術，讓元件的ft可達到33.5 GHz(氧化鋁)和43 GHz(氮化鋁)；fmax可達到23 GHz(氧化鋁)和26 GHz(氮化鋁)。在通道長度為差不多的情況下，已經能媲美於做在碳化矽基板上的例子，成功地達到降低製程成本的目標，且亦在倍頻器上展現了其應用價值。本論文的閘極氧化層是藉由自然乾式氧化的方式所形成，除了可得到良好品質的閘極電容(950 ~ 1100 nF/cm^2)，亦讓整體的製程溫度可以低於200度，因此在後段製程(back-end-of line, BEOL)的應用上有很高的潛力。

Since A. K. Geim and K. S. Novoselov peeled off successfully one layer graphite from the highly orientated pyrolytic graphite (HOPG) by mechanical exfoliation in 2004, numerous novel researches about graphene, a isolated mono-atomic carbon layer constituted of two-dimentional honeycomb lattice building block, had be triggered off. Due to graphene's fantastic and excellent properties, it is one of the candidates which are the new star for electronics industry in the next generation.

Today, electronic communication products can be seen everywhere. It shorten the distance between people and is one of the essential factors to expedite scientific and technological progress. Due to a large carrier mobility and long-range ballistic transport, many high-frequency applications of graphene-based literatures were published. Although high-speed graphenetronic built on silicon carbide substrate (SiC) has excellent high-frequency characteristics, but the cost is very expensive and mass production is difficult.

We shows state-of-the-art of high-speed graphenetronics built on insulator substrates such as sapphire and aluminum nitride. With the T-shaped gate and self-alignment, high-speed graphenetronics have achieved recorded unity current gain cut-off frequency of 43 GHz and maximum oscillation frequency of 26 GHz realized with transferred graphene films on AlN substrate. The performance has able to compare favourably with the case on SiC substrates. We can get high quality gate oxide layer (950~1100 nF/cm^2) by naturally dry oxidation, and complete the entire fabrication flow below 200 degrees. Therefore, it engaged to paves a way for seamless heterogeneous three-dimensional (3D) system integration with graphene-last flow in Si fab technology, where graphene IC's back-end-of line (BEOL) can be co-integrated with stand Si CMOS.

[1] J. Bardeen and W. H. Brattain, “The transistor, a semi-conductor triode,” Phys. Rev., vol. 74, pp. 230–231, 1948.
[2] “The first bipolar junction transistor,” http://ece.uprm.edu/mtoledo/6055/.
[3] “The first metal-oxide-semiconductor FET,” http://materias.fi.uba.ar/6648DS/.
[4] “The first integrated circuit,” http://en.wikipedia.org/wiki/Integrated_circuit.
[5] “The first silicon integrated circuit chip,” http:// www.swinnovation.co.uk/ 2011/05/
southwest-celebrates-50-years-of-the-silicon-microchip/.
[6] “Intel roadmap,” http:// www.zdnet.com/ intels-moores-law-may-ultimately-meeteconomic-limits-7000005781/.
[7] H. Park, J. Park, A. K. L. Lim, E. H. Anderson, A. P. Alivisatos, and P. L. McEuen,
“Nanomechanical oscillations in a single-C60 transistor,” Nature, vol. 407, pp. 57–60, 2000.
[8] C. M. Varma, J. Zaanen, and K. Raghavachari, “Superconductivity in the fullerenes,” Science, vol. 254, pp. 989–992, 1991.
[9] P. Peumans and S. R. Forrest, “Very-high-efficiency double-heterostructure copper phthalocyanine/C60 photovoltaic cells,” Appl. Phys. Lett., vol. 79, pp. 126–128, 2001.
[10] S. Iijima, “Helical microtubules of graphitic carbon,” Nature, vol. 354, pp. 56–58, 1991.
[11] S. Iijima and T. Ichihashi, “Single-shell carbon nanotubes of 1-nm diameter,” Nature, vol. 364, pp. 737–737, 1993.
[12] F. Kreupl, A. P. Graham, M. Liebau, G. S. Duesberg, R. Seidel, and E. Unger, “Carbon nanotubes for interconnect applications,” IEEE Int. Electron Devices Meet. Tech. Dig.,
pp. 683–686, 2004.
[13] H. Zhang, J. A. Payne, A. A. Pesetski, J. E. Baumgardner, W. Miller, K. Krishnaswamy, A. Jazairy, J. X. Przybysz, and J. D. Adam, “High performance carbon nanotube RF electronics,” Device Res. Conf., pp. 13–14, 2008.
[14] L. Ding, Z. Y. Zhang, S. B. Liang, T. Pei, S. Wang, Y. Li, W. W. Zhou, J. Liu, and L. M. Peng, “CMOS-based carbon nanotube pass-transistor logic integrated circuits,” Nat. Commun., vol. 3, 2012.
[15] K. S. Novoselov, A. K. Geim, S. V. Morozov, D. Jiang, Y. Zhang, S. V. Dubonos, I. V. Grigorieva, and A. A. Firsov, “Electric field effect in atomically thin carbon films,” Science, vol. 306, pp. 666–669, 2004.
[16] K. I. Bolotin, K. J. Sikes, Z. Jiang, M. Klima, G. Fudenberg, J. Hone, P. Kim, and H. L. Stormer, “Ultrahigh electron mobility in suspended graphene,” Solid State Commun., vol. 146, pp. 351–355, 2008.
[17] R. Murali, Y. X. Yang, K. Brenner, T. Beck, and J. D. Meindl, “Breakdown current density of graphene nanoribbons,” Appl. Phys. Lett., vol. 94, 2009.
[18] C. Lee, X. D. Wei, J. W. Kysar, and J. Hone, “Measurement of the elastic properties and intrinsic strength of monolayer graphene,” Science, vol. 321, pp. 385–388, 2008.
[19] R. R. Nair, P. Blake, A. N. Grigorenko, K. S. Novoselov, T. J. Booth, T. Stauber, N. M. R. Peres, and A. K. Geim, “Fine structure constant defines visual ransparency of graphene,” Science, vol. 320, pp. 1308–1308, 2008.
[20] T. Palacios, A. Hsu, and H. Wang, “Applications of graphene devices in RF communications,” IEEE Commun. Mag., vol. 48, pp. 122–128, 2010.
[21] “Carbon family,” http:// spectrum.ieee.org/ semiconductors/ materials/ grapheneelectronics-
unzipped.
[22] N. Petrone, I. Meric, J. Hone, and K. L. Shepard, “Graphene field-effect transistors with gigahertz-frequency power gain on flexible substrates,” Nano Lett., vol. 13, pp. 121–125, 2013.
[23] Z. L. Guo, R. Dong, P. S. Chakraborty, N. Lourenco, J. Palmer, Y. K. Hu, M. Ruan, J. Hankinson, J. Kunc, J. D. Cressler, C. Berger, and W. A. de Heer, “Record maximum oscillation frequency in C-face epitaxial graphene transistors,” Nano Lett., vol. 13, pp. 942–947, 2013.
[24] Y. Q. Wu, K. A. Jenkins, A. Valdes-Garcia, D. B. Farmer, Y. Zhu, A. A. Bol, C. Dimitrakopoulos, W. J. Zhu, F. N. Xia, P. Avouris, and Y. M. Lin, “State-of-the-art graphene high-frequency electronics,” Nano Lett., vol. 12, pp. 3062–3067, 2012.
[25] S. Das and J. Appenzeller, “An all-graphene radio frequency low noise amplifier,” IEEE Radio Freq. Integr. Circ. Symp., pp. 1–4, 2011.
[26] S. J. Han, K. A. Jenkins, A. V. Garcia, A. D. Franklin, A. A. Bol, and W. Haensch, “Highfrequency graphene voltage amplifier,” Nano Lett., vol. 11, pp. 3690–3693, 2011.
[27] H. Wang, A. Hsu, J. Wu, J. Kong, and T. Palacios, “Graphene-based ambipolar RF mixers,” IEEE Electron Device Lett., vol. 31, pp. 906–908, 2010.
[28] O. Habibpour, S. Cherednichenko, J. Vukusic, K. Yhland, and J. Stake, “A subharmonic graphene FET mixer,” IEEE Electron Device Lett., vol. 33, pp. 71–73, 2012.
[29] J. S. Moon, H. C. Seo, M. Antcliffe, D. Le, C. McGuire, A. Schmitz, L. O. Nyakiti, D. K. Gaskill, P. M. Campbell, K. M. Lee, and P. Asbeck, “Graphene FETs for zero-bias linear
resistive FET mixers,” IEEE Electron Device Lett., vol. 34, pp. 465–467, 2013.
[30] H. Wang, D. Nezich, J. Kong, and T. Palacios, “Graphene frequency multipliers,” IEEE Electron Device Lett., vol. 30, pp. 547–549, 2009.
[31] H. Wang, A. Hsu, K. Ki Kang, J. Kong, and T. Palacios, “Gigahertz ambipolar frequency multiplier based on CVD graphene,” IEEE Int. Electron Device Meet., pp. 23.6.1–23.6.4, 2010.
[32] H. Wang, A. Hsu, B. Mailly, K. Ki Kang, J. Kong, and T. Palacios, “Towards ubiquitous RF electronics based on graphene,” IEEE Int. Micoro. Symp. Dig., pp. 1–3, 2012.
[33] R. Cheng, J. Bai, L. Liao, H. Zhou, Y. Chen, L. Liu, Y.-C. Lin, S. Jiang, Y. Huang, and X. Duan, “High-frequency self-aligned graphene transistors with transferred gate stacks,” Proc. Natl. Acad. Sci., vol. 109, pp. 11588–11592, 2012.
[34] P. R. Wallace, “The band theory of graphite,” Phys. Rev., vol. 71, pp. 622–634, 1947.
[35] J. Yao, Y. Sun, M. Yang, and Y. X. Duan, “Chemistry, physics and biology of graphenebased nanomaterials: new horizons for sensing, imaging and medicine,” J. Mater. Chem., vol. 22, pp. 14313–14329, 2012.
[36] A. K. Geim and K. S. Novoselov, “The rise of graphene,” Nat. Mater., vol. 6, pp. 183–191, 2007.
[37] A. C. Ferrari, “Raman spectroscopy of graphene and graphite: Disorder, electron-phonon coupling, doping and nonadiabatic effects,” Solid State Commun., vol. 143, pp. 47–57, 2007.
[38] C. L. Kane, “Materials science - erasing electron mass,” Nature, vol. 438, pp. 168–170, 2005.
[39] P. E. Allain and J. N. Fuchs, “Klein tunneling in graphene: optics with massless electrons,” Eur. Phys. J. B, vol. 83, pp. 301–317, 2011.
[40] M. I. Katsnelson, “Zitterbewegung, chirality, and minimal conductivity in graphene,” Eur. Phys. J. B, vol. 51, pp. 157–160, 2006.
[41] J. Tworzydlo, B. Trauzettel, M. Titov, A. Rycerz, and C. W. J. Beenakker, “Sub-poissonian shot noise in graphene,” Phys. Rev. Lett., vol. 96, 2006.
[42] K. S. Novoselov, A. K. Geim, S. V. Morozov, D. Jiang, M. I. Katsnelson, I. V. Grigorieva, S. V. Dubonos, and A. A. Firsov, “Two-dimensional gas of massless dirac fermions in
graphene,” Nature, vol. 438, pp. 197–200, 2005.
[43] S. Das Sarma, S. Adam, E. H. Hwang, and E. Rossi, “Electronic transport in twodimensional graphene,” Rev. Mod. Phys., vol. 83, pp. 407–470, 2011.
[44] Y. W. Tan, Y. Zhang, K. Bolotin, Y. Zhao, S. Adam, E. H. Hwang, S. Das Sarma, H. L. Stormer, and P. Kim, “Measurement of scattering rate and minimum conductivity in
graphene,” Phys. Rev. Lett., vol. 99, 2007.
[45] J. H. Chen, C. Jang, S. Adam, M. S. Fuhrer, E. D. Williams, and M. Ishigami, “Chargedimpurity scattering in graphene,” Nat. Phys., vol. 4, pp. 377–381, 2008.
[46] S. Das Sarma and E. H. Hwang, “Density-dependent electrical conductivity in suspended graphene: Approaching the dirac point in transport,” Phys. Rev. B, vol. 87, 2013.
[47] J. C. Meyer, A. K. Geim, M. I. Katsnelson, K. S. Novoselov, T. J. Booth, and S. Roth, “The structure of suspended graphene sheets,” Nature, vol. 446, pp. 60–63, 2007.
[48] J. Martin, N. Akerman, G. Ulbricht, T. Lohmann, J. H. Smet, K. Von Klitzing, and A. Yacoby, “Observation of electron-hole puddles in graphene using a scanning single-electron transistor,” Nat. Phys., vol. 4, pp. 144–148, 2008.
[49] E. H. Hwang, S. Adam, and S. Das Sarma, “Carrier transport in two-dimensional graphene layers,” Phys. Rev. Lett., vol. 98, 2007.
[50] S. V. Morozov, K. S. Novoselov, M. I. Katsnelson, F. Schedin, D. C. Elias, J. A. Jaszczak, and A. K. Geim, “Giant intrinsic carrier mobilities in graphene and its bilayer,” Phys. Rev. Lett., vol. 100, 2008.
[51] B. Huard, N. Stander, J. A. Sulpizio, and D. Goldhaber-Gordon, “Evidence of the role of contacts on the observed electron-hole asymmetry in graphene,” Phys. Rev. B, vol. 78,
2008.
[52] J. H. Chen, C. Jang, S. D. Xiao, M. Ishigami, and M. S. Fuhrer, “Intrinsic and extrinsic performance limits of graphene devices on SiO2,” Nat. Nanotechnol., vol. 3, pp. 206–209, 2008.
[53] S. Fratini and F. Guinea, “Substrate-limited electron dynamics in graphene,” Phys. Rev. B, vol. 77, 2008.
[54] I. Meric, M. Y. Han, A. F. Young, B. Ozyilmaz, P. Kim, and K. L. Shepard, “Current saturation in zero-bandgap, top-gated graphene field-effect transistors,” Nat. Nanotechnol.,
vol. 3, pp. 654–659, 2008.
[55] A. Konar, T. Fang, and D. Jena, “Effect of high-k gate dielectrics on charge transport in graphene-based field effect transistors,” Phys. Rev. B, vol. 82, p. 115452, 2010.
[56] S. J. Han, S. Oida, K. A. Jenkins, D. Lu, and Y. Zhu, “Multifinger embedded T-shaped gate graphene RF transistors with high f(max)/f(t) ratio,” IEEE Electron Device Lett., vol. 34, pp. 1340–1342, 2013.
[57] Y. Q. Wu, D. B. Farmer, A. Valdes-Garcia, W. J. Zhu, K. A. Jenkins, C. Dimitrakopoulos, P. Avouris, and Y. M. Lin, “Record high RF performance for epitaxial graphene transistors,” IEEE Int. Electron Device Meet., 2011.
[58] N. Meng, J. F. Fernandez, E. Pichonat, O. Lancry, D. Vignaud, G. Dambrine, and H. Happy, “RF characterization of epitaxial graphene nano ribbon field effect transistor,”
IEEE Int. Micro. Symp. Dig., pp. 1–3, 2011.
[59] L. Yu-Ming, K. A. Jenkins, J. Ott, C. Dimitrakopoulos, D. B. Farmer, W. Yanqing, A. Grill, and P. Avouris, “Electrical characterization of wafer-scale epitaxial graphene and its RF applications,” IEEE Int. Micro. Symp. Dig., pp. 1–4, 2011.
[60] J. A. Robinson, M. Hollander, M. LaBella, K. A. Trumbull, R. Cavalero, and D. W. Snyder, “Epitaxial graphene transistors: Enhancing performance via hydrogen intercalation,” Nano Lett., vol. 11, pp. 3875–3880, 2011.
[61] S. S. Ng, Z. Hassan, and H. Abu Hassan, “Experimental and theoretical studies of surface phonon polariton of AlN thin film,” Appl. Phys. Lett., vol. 90, 2007.
[62] Z. Y. Zhang, H. L. Xu, H. Zhong, and L. M. Peng, “Direct extraction of carrier mobility in graphene field-effect transistor using current-voltage and capacitance-voltage measurements,” Appl. Phys. Lett., vol. 101, 2012.
[63] J. S. Moon, D. Curtis, M. Hu, D. Wong, C. McGuire, P. M. Campbell, G. Jernigan, J. L. Tedesco, B. VanMil, R. Myers-Ward, C. Eddy, and D. K. Gaskill, “Epitaxial-graphene RF field-effect transistors on Si-face 6H-SiC substrates,” IEEE Electron Device Lett., vol. 30, pp. 650–652, 2009.
[64] E. B.Rosa., “The self and mutual inductances of linear conductors,” Sci. Paper, vol. 4, pp. 301–344, 1908.
[65] H. A. Wheeler, “Formulas for the skin effect,” Proc. IRE, vol. 30, pp. 412–424, 1942.
[66] “Skin effect,” http://www.radartutorial.eu/03.linetheory/tl07.en.html.
[67] A. Badmaev, Y. C. Che, Z. Li, C. Wang, and C. W. Zhou, “Self-aligned fabrication of graphene RF transistors with T-shaped gate,” ACS Nano, vol. 6, pp. 3371–3376, 2012.
[68] Y. M. Lin, K. A. Jenkins, A. Valdes-Garcia, J. P. Small, D. B. Farmer, and P. Avouris, “Operation of graphene transistors at gigahertz frequencies,” Nano Lett., vol. 9, pp. 422–426, 2009.
[69] L. Liao, Y. C. Lin, M. Q. Bao, R. Cheng, J. W. Bai, Y. A. Liu, Y. Q. Qu, K. L. Wang, Y. Huang, and X. F. Duan, “High-speed graphene transistors with a self-aligned nanowire gate,” Nature, vol. 467, pp. 305–308, 2010.
[70] I. Meric, C. R. Dean, S. J. Han, L. Wang, K. A. Jenkins, J. Hone, and K. L. Shepard, “High-frequency performance of graphene field effect transistors with saturating ivcharacteristics,” IEEE Int. Electron Device Meet., 2011.
[71] D. W. Park, T. H. Chang, S. Mikael, J. H. Seo, P. F. Nealey, and Z. Q. Ma, “Graphene RF transistors with buried bottom gate,” IEEE Top. Meet. Integr. Circ., pp. 84–86, 2013.
[72] Y. Q. Wu, Y. M. Lin, A. A. Bol, K. A. Jenkins, F. N. Xia, D. B. Farmer, Y. Zhu, and P. Avouris, “High-frequency, scaled graphene transistors on diamond-like carbon,” Nature,
vol. 472, pp. 74–78, 2011.
[73] L. Liao, J. W. Bai, R. Cheng, H. L. Zhou, L. X. Liu, Y. Liu, Y. Huang, and X. F. Duan, “Scalable fabrication of self-aligned graphene transistors and circuits on glass,” Nano Lett., vol. 12, pp. 2653–2657, 2012.
[74] M. I. Katsnelson and A. K. Geim, “Electron scattering on microscopic corrugations in graphene,” Philos. Trans. R. Soc. A., vol. 366, pp. 195–204, 2008.
[75] X. R. Wang, S. M. Tabakman, and H. J. Dai, “Atomic layer deposition of metal oxides on pristine and functionalized graphene,” J. Am. Chem. Soc., vol. 130, pp. 8152–8153, 2008.
[76] Z. H. Ni, H. M. Wang, Y. Ma, J. Kasim, Y. H. Wu, and Z. X. Shen, “Tunable stress and controlled thickness modification in graphene by annealing,” ACS Nano, vol. 2, pp. 1033–1039, 2008.
[77] B. Fallahazad, S. Kim, L. Colombo, and E. Tutuc, “Dielectric thickness dependence of carrier mobility in graphene with HfO2 top dielectric,” Appl. Phys. Lett., vol. 97, 2010.
[78] D. B. Farmer, H. Y. Chiu, Y. M. Lin, K. A. Jenkins, F. N. Xia, and P. Avouris, “Utilization of a buffered dielectric to achieve high field-effect carrier mobility in graphene transistors,” Nano Lett., vol. 9, pp. 4474–4478, 2009.
[79] M. J. Hollander, M. LaBella, Z. R. Hughes, M. Zhu, K. A. Trumbull, R. Cavalero, D. W. Snyder, X. J. Wang, E. Hwang, S. Datta, and J. A. Robinson, “Enhanced transport and
transistor performance with oxide seeded high-k gate dielectrics on wafer-scale epitaxial graphene,” Nano Lett., vol. 11, pp. 3601–3607, 2011.
[80] K. Gloos, P. J. Koppinen, and J. P. Pekola, “Properties of native ultrathin aluminium oxide tunnel barriers,” J. Phys. Condens. Mat., vol. 15, pp. 1733–1746, 2003.
[81] C. C. Lu, Y. C. Lin, C. H. Yeh, J. C. Huang, and P. W. Chiu, “High mobility flexible graphene field-effect transistors with self-healing gate dielectrics,” ACS Nano, vol. 6, pp. 4469–4474, 2012.
[82] “Scan electron microscopy,” http://www.ammrf.org.au/myscope/sem/practice/principles/
layout.php.
[83] “Variable pressure scanning electron microscopy,” http:// www.spectral.se/ wp/?post_type=new_systems&p=641.
[84] P. Joshi, H. E. Romero, A. T. Neal, V. K. Toutam, and S. A. Tadigadapa, “Intrinsic doping and gate hysteresis in graphene field effect devices fabricated on SiO2 substrates,” J. Phys. Condens. Mat., vol. 22, 2010.
[85] D. B. Farmer, R. Golizadeh-Mojarad, V. Perebeinos, Y.-M. Lin, G. S. Tulevski, J. C. Tsang, and P. Avouris, “Chemical doping and electron-hole conduction asymmetry in graphene devices,” Nano Lett., vol. 9, pp. 388–392, 2008.
[86] H. Wang, A. Hsu, D. S. Lee, K. K. Kim, J. Kong, and T. Palacios, “Delay analysis of graphene field-effect transistors,” IEEE Electron Device Lett., vol. 33, pp. 324–326, 2012.
[87] X. Li, E. A. Barry, J. M. Zavada, M. B. Nardelli, and K. W. Kim, “Surface polar phonon dominated electron transport in graphene,” Appl. Phys. Lett., vol. 97, 2010.
[88] I. T. Lin and J. M. Liu, “Surface polar optical phonon scattering of carriers in graphene on various substrates,” Appl. Phys. Lett., vol. 103, 2013.
[89] C. Wang, J.-C. Chien, H. Fang, K. Takei, J. Nah, E. Plis, S. Krishna, A. M. Niknejad, and A. Javey, “Self-aligned, extremely high frequency III-V metal-oxide-semiconductor field-effect transistors on rigid and flexible substrates,” Nano Lett., vol. 12, pp. 4140–4145, 2012.