光通訊產業朝向整合光學元件的趨勢發展，當光由光纖進入波導時，波導與空氣的介面會因為拋光製程的好壞，而造成損耗，且拋光製程非常耗時，為了達到減少損耗及減少製程時間的目的，在本論文中利用光纖取代波導，並在矽基板上製作一個立體結構的光電晶體，將光直接照射到元件的主動區上。
在光纖取代波導的這方面，利用KOH非等向性蝕刻的特性，在矽基板上製作出V型溝槽，並且蝕刻出足夠的深度能容納直徑為125 μm的光纖。而元件結構則是在P型矽基板上摻雜兩個N型區，中間留下主動區形成光電晶體，其中摻雜的方式大多都是使用離子佈植的方式，但是所需的成本相當高，為了降低成本，因此採用Spin-on Dopant(SOD)擴散摻雜的方式，來達到摻雜N型區域的效果。
在本論文中的最後將兩者作為結合，形成一個有著立體結構的整合型元件，光電晶體的主動區在側面，而光則由被固定在V型溝槽的光纖照射至光電晶體，照射在光電晶體的光強度則與所產生的光電流成正比。

The developmental trend of optical communication industry is moving steadily towards the development of optoelectronic integrated circuits (OEICs). In order to reduce the loss of light coupled from the fiber to the waveguide, a time-consuming polishing process is implemented in a judicious fashion. In some integration cases, it is possible to bypass the fiber-waveguide coupling by allowing fiber directly interacting with the electronic devices. With this spirit in mind, in this thesis a three-dimensional structure of phototransistor is fabricated in silicon substrate with the light directly coupled the active junction area.
Concerning the realization of a direct fiber coupling, a V-groove structure was fabricated in the silicon substrate using potassium hydroxide (KOH) anisotropic etching technique to etch Si to an appropriate depth in order to accommodate an optical fiber with a diameter of 125 μm. The proposed phototransistor involves a p-type silicon substrate doped with two separate n-type areas. In order to avoid the use of cumbersome and costly ion implantation, the n-doped regions were achieved by using a significantly simple and cheaper spin-on dopant (SOD) diffusion method to carry out the doping process in n region.
The major purpose of thesis is to evaluate the performance of a direct fiber-coupled three-dimensional phototransistors. The active region of the phototransistor located on the sidewall is to be irradiated by the light emitted by the optical fiber permanently fixed in the V-groove. It was found that the generated photocurrent is directly proportional to the light intensity irradiated on the phototransistor.

[1] D. Cristea, F. Craciunoiu, and M. Caldararu, "Silicon optoelectronic integrated circuits for MOEMS," in Symposium on Design, Test, Integration, and Packaging of MEMS/MOEMS, 2000, pp. 516-525.
[2] M. C. Wu, "Micromachining for optical and optoelectronic systems," Proceedings of the IEEE, vol. 85, pp. 1833-1856, 1997.
[3] R. A. Soref, "Silicon-based optoelectronics," Proceedings of the IEEE, vol. 81, pp. 1687-1706, 1993.
[4] P. J. Holmes and P. Handler, "The electrochemistry of semiconductors," ed: The Electrochemical Society, 1962.
[5] H. Seidel, L. Csepregi, A. Heuberger, and H. Baumgärtel, "Anisotropic etching of crystalline silicon in alkaline solutions I. Orientation dependence and behavior of passivation layers," Journal of the electrochemical society, vol. 137, pp. 3612-3626, 1990.

[6] K. Sato, M. Shikida, Y. Matsushima, T. Yamashiro, K. Asaumi, Y. Iriye, et al., "Characterization of orientation-dependent etching properties of single-crystal silicon: effects of KOH concentration," Sensors and Actuators A: Physical, vol. 64, pp. 87-93, 1998.
[7] A. Priyadarshi, L. Fen, S. Mhaisalkar, V. Kripesh, and A. Asundi, "Fiber misalignment in silicon V-groove based optical modules," Optical Fiber Technology, vol. 12, pp. 170-184, 2006.
[8] M. Hoffmann, P. Kopka, D. Nüsse, and E. Voges, "Fibre-optical MEMS switches based on bulk silicon micromachining," Microsystem technologies, vol. 9, pp. 299-303, 2003.
[9] D. J. Sadler, M. J. Garter, C. H. Ahn, S. Koh, and A. L. Cook, "Reflectivity of micromachined {111}-oriented silicon mirrors for optical input/output couplers," in Micromachining and Microfabrication'96, 1996, pp. 45-54.
[10] Y. Uenishi, M. Tsugai, and M. Mehregany, "Micro-opto-mechanical devices fabricated by anisotropic etching of (110) silicon," Journal of Micromechanics and Microengineering, vol. 5, p. 305, 1995.

[11] L. Rosengren, L. Smith, and Y. B¨acklund, “Micromachined optical planes and reflectors in silicon,” Sensors and Actuators A: Physical, vol. 41, pp. 330-333, 1994.
[12] L. Smith, L. Tenerz, and B. Hok, "Silicon micromachined (2× 2) optocoupler," in Proc. SPIE, 1990, pp. 91-5.
[13] C. Marxer, C. Thio, M.-A. Gretillat, N. F. de Rooij, R. Battig, O. Anthamatten, et al., "Vertical mirrors fabricated by deep reactive ion etching for fiber-optic switching applications," Journal of Microelectromechanical Systems, vol. 6, pp. 277-285, 1997.
[14] K. P. Rola, K. Ptasiński, A. Zakrzewski, and I. Zubel, "Silicon 45 micromirrors fabricated by etching in alkaline solutions with organic additives," Microsystem Technologies, vol. 20, pp. 221-226, 2014.
[15] K. P. Rola and I. Zubel, "45° micromirrors fabricated by silicon anisotropic etching in KOH solutions saturated with alcohols," in Students and Young Scientists Workshop, 2011 International, 2011, pp. 110-114.
[16] P. Pal, A. Ashok, S. Haldar, Y. Xing, and K. Sato, "Anisotropic etching in low-concentration KOH: effects of surfactant concentration," Micro & Nano Letters, vol. 10, pp. 224-228, 2015.

[17] D. Resnik, D. Vrtacnik, U. Aljancic, M. Mozek, and S. Amon, "The role of Triton surfactant in anisotropic etching of {1 1 0} reflective planes on (1 0 0) silicon," Journal of Micromechanics and Microengineering, vol. 15, p. 1174, 2005.
[18] K. P. Rola and I. Zubel, "Triton surfactant as an additive to KOH silicon etchant," J Microelectromech Syst, vol. 22, pp. 1373-1382, 2013.
[19] M. Shikida, K. Sato, K. Tokoro, and D. Uchikawa, "Differences in anisotropic etching properties of KOH and TMAH solutions," Sensors and Actuators A: Physical, vol. 80, pp. 179-188, 2000.
[20] D. J. Sadler, M. J. Garter, C. H. Ahn, S. Koh, and A. L. Cook, "Optical reflectivity of micromachined {111}-oriented silicon mirrors for optical input-output couplers," Journal of Micromechanics and Microengineering, vol. 7, p. 263, 1997.
[21] D. Resnik, D. Vrtacnik, U. Aljancic, M. Mozek, and S. Amon, "The role of Triton surfactant in anisotropic etching of {1 1 0} reflective planes on (1 0 0) silicon," Journal of Micromechanics and Microengineering, vol. 15, p. 1174, 2005.
[22] K. P. Rola and I. Zubel, "Triton surfactant as an additive to KOH silicon etchant," J Microelectromech Syst, vol. 22, pp. 1373-1382, 2013.
[23] P. Pal, A. Ashok, S. Haldar, Y. Xing, and K. Sato, "Anisotropic etching in low-concentration KOH: effects of surfactant concentration," Micro & Nano Letters, vol. 10, pp. 224-228, 2015.
[24] C. C. Hu, "Modern Semiconductor Devices for Integrated Circuits," Part I: Electrons and holes in a semiconductor, 2011.
[25] "半導體製程設備見習班SM01-1講義," 國家奈米元件實驗室, 2016
[26] T. Nguyen Nhu, Spin-on glass: Materials and applications in advanced IC technologies, 1999.
[27] Donald A. Neamen. “Semiconductor physics and devices 4th,” 2011
[28] H. Zhu, L. Zhou, X. Li, and J. Chen, "All-silicon near-infrared phototransistor based on surface-state absorption," in Opto-Electronics and Communications Conference (OECC), 2015, 2015, pp. 1-2.
[29] H. Beneking, "Gain and bandwidth of fast near-infrared photodetectors: a comparison of diodes, phototransistors, and photoconductive devices," IEEE Transactions on Electron Devices, vol. 29, pp. 1420-1431, 1982.
[30] M. Geis, S. Spector, M. Grein, J. Yoon, D. Lennon, and T. Lyszczarz, "Silicon waveguide infrared photodiodes with> 35 GHz bandwidth and phototransistors with 50 AW-1 response," Optics express, vol. 17, pp. 5193-5204, 2009.
[31] S.-Y. Huang, S. Esener, and S. H. Lee, "npn silicon lateral phototransistors for hybrid integrated optical circuits," IEEE Transactions on Electron Devices, vol. 33, pp. 433-441, 1986
[32] http://ezphysics.nchu.edu.tw/prophys/basicexp/expnote/hall/hall_97Feb.pdf
[33] D. Resnik, D. Vrtacnik, U. Aljancic, M. Mozek, and S. Amon, "The role of Triton surfactant in anisotropic etching of {1 1 0} reflective planes on (1 0 0) silicon," Journal of Micromechanics and Microengineering, vol. 15, p. 1174, 2005.
[34] https://www.tf.unikiel.de/matwis/amat/elmat_en/kap_6/backbone/r6_2_1.html
[35] K. P. Rola and I. Zubel, "45° micromirrors fabricated by silicon anisotropic etching in KOH solutions saturated with alcohols," in Students and Young Scientists Workshop, 2011 International, 2011, pp. 110-114.
[36] http://www.cleanroom.byu.edu/KOH.phtml
[37] http://mnm.physics.mcgill.ca/content/s1813-spin-coating
[38] 徐懋騰, "應用矽基版製作與分析光波導調變元件" 國立成功大學微機電系統工程研究所, 2006
[39] http://www.ndl.org.tw/docs/devices/CF/T21_E_2.doc
[40] D. Mathiot, A. Lachiq, A. Slaoui, S. Noël, J. Muller, and C. Dubois, "Phosphorus diffusion from a spin-on doped glass (SOD) source during rapid thermal annealing," Materials science in semiconductor processing, vol. 1, pp. 231-236, 1998.
[41] J. Jourdan, Y. Veschetti, S. Dubois, T. Desrues, and R. Monna, "Formation of Boron‐doped region using spin‐on dopant: investigation on the impact of metallic impurities," Progress in Photovoltaics: Research and Applications, vol. 16, pp. 379-387, 2008.
[42] K. Ali, S. A. Khan, and M. M. Jafri, "Spin-on doping (SOD) and diffusion temperature effect on recombinations/ideality factor for solar cell applications," Chalcogenide Lett, vol. 9, pp. 457-463, 2012.
[43] E. Radziemska, "Dark I–U–T measurements of single crystalline silicon solar cells," Energy Conversion and Management, vol. 46, pp. 1485-1494, 2005.