OSA's Digital Library

Journal of Lightwave Technology

Journal of Lightwave Technology


  • Vol. 27, Iss. 17 — Sep. 1, 2009
  • pp: 3861–3873

Design and Analysis of Metal-Oxide-Semiconductor–Capacitor Microring Optical Modulator With Solid-Phase-Crystallization Poly-Silicon Gate

Chih T'sung Shih, Zhi Wei Zeng, and Shiuh Chao

Journal of Lightwave Technology, Vol. 27, Issue 17, pp. 3861-3873 (2009)

View Full Text Article

Acrobat PDF (1131 KB)

Browse Journals / Lookup Meetings

Browse by Journal and Year


Lookup Conference Papers

Close Browse Journals / Lookup Meetings

Article Tools

  • Export Citation/Save Click for help


We present a rigorous electrical and optical analysis for a metal-oxide-semiconductor (MOS)–capacitor microring optical modulator on silicon-on-insulator (SOI) with a low-mobility and high optical loss polysilicon gate that could be fabricated by the complementary metal-oxide-semiconductor (CMOS)-compatible solid-phase-crystallization (SPC) process. Critical coupling was designed for the 25.5 $\mu$m radius rib-waveguide microring. Modulation speed, operating power at 3.3 V operating voltage, and insertion loss (IL) were analyzed with respect to the doping level of the SPC p-polysilicon gate and the n-crystalline silicon channel. $4.6\times 10^{-2}{\hbox {pJ}}/{\mu {\hbox {m}}}^{2}$ operating power per switch can be achieved with 74 GHz modulation speed for $3\times 10^{18}\ {\hbox {cm}}^{-3}$ doping level in both the SPC p-polysilicon gate and the n-crystalline silicon channel. For 40 GHz operation, 10–12 dB IL is achievable with the SPC polysilicon, and 9 dB IL is achievable with the well-annealed polysilicon that is lossless. Tolerance of the critical coupling to the gap width variation, temperature drifting of the microring, and wavelength drifting of the light source were analyzed and discussed extensively, and the extinction ratio (ER) was estimated for various situations. The 90 nm CMOS fabrication specification, if applied to the gap width variation of the microring, would leave a large margin in the ER to other sources of the critical coupling deviation. We found that $\sim\pm 0.2^{\circ}{\rm C}$ temperature stability for the microring and the light source is required for a minimum ER of 5 dB if temperatures of both elements are controlled independently. Comparison between the MOS–capacitor modulators with microring and with Mach–Zehnder types was analyzed and discussed. In contrast to the Mach–Zehnder modulator, the modulation speed of the microring can be pushed up by increasing the doping level up to $\sim$1$\times 10^{18}\ {\hbox {cm}}^{-3}$ without significantly increasing the IL.

© 2009 IEEE

Chih T'sung Shih, Zhi Wei Zeng, and Shiuh Chao, "Design and Analysis of Metal-Oxide-Semiconductor–Capacitor Microring Optical Modulator With Solid-Phase-Crystallization Poly-Silicon Gate," J. Lightwave Technol. 27, 3861-3873 (2009)

Sort:  Year  |  Journal  |  Reset


  1. R. A. Soref, P. J. Lorenzo, "All-silicon active and passive guided-wave components for = 1.3 and 1.6 $\mu{\rm m}$," IEEE J. Quant. Electron. 22, 873-879 (1986).
  2. A. Liu, R. Jones, L. Liao, D. Samara-Rubio, D. Rubin, O. Cohen, R. Nicolaescu, M. Paniccia, "A high-speed silicon optical modulator based on a metal-oxide-semiconductor capacitor," Nature 427, 615-618 (2004).
  3. Q. Xu, B. Schmidt, S. Pradhan, M. Lipson, "Micrometre-scale silicon electro-optic modulator," Nature 435, 325-327 (2005).
  4. R. D. Kekatpure, M. L. Brongersma, "Design of a silicon-based field-effect electro-optic modulator with enhanced light-charge interaction," Opt. Lett. 29, 2149-2151 (2005).
  5. L. Liao, D. S. Rubio, M. Morse, A. Liu, D. Hodge, "High speed silicon Mach-Zehender modulator," Opt. Express 13, (2005) pp. 3139-3125.
  6. R. A. Soref, B. R. Bennett, "Electrooptical effects in silicon," IEEE J. Quantum Electron. 23, 123-129 (1987).
  7. C. T. Shih, S. Chao, "Simplified numerical method for analyzing TE-like modes in 3-D circularly bent dielectric rib waveguide by solving two 1-D eigenvalue equations," J. Opt. Soc. Am. B 25, 1031-1037 (2008).
  8. S. M. Sze, VLSI Technology (McGraw-Hill, 1988) pp. 233-271.
  9. M. Takabatake, J. I. Ohwada, Y. A. Ono, K. Ono, A. Mimura, N. Konishi, "CMOS circuits for peripheral circuit integrated poly-Si TFT LCD fabricated at low temperature below 600 $^{\circ}{\rm C}$," IEEE Trans. Electron Devices 38, 1303-1309 (1991).
  10. S. W. Lee, T. H. Ihn, S. K. Joo, "Fabrication of high-mobility p-channel poly-Si thin film transistors by self-aligned metal-induced lateral crystallization," IEEE Electron Device Lett. 17, 407-409 (1996).
  11. J. S. Foresi, M. R. Black, A. M. Agarwal, L. C. Kimerling, "Losses in polycrystalline silicon waveguides," Appl. Phys. Lett. 68, 2052-2054 (1996).
  12. L. Liao, Low Loss Polysilicon Waveguides for Silicon Photonics M.S. thesis Dept. Materials Sci. and Eng. Massachusetts Institute of TechnologyCambridgeMA (1997).
  13. A. M. Ghosh, C. Fishman, T. Feng, "Theory of the electrical and photovoltaic properties of polycrystalline silicon," J. Appl. Phys. 51, 446-454 (1980).
  14. D. R. Lim, Device Integration for Silicon Microphotonic Platforms Ph.D. dissertation Dept. Elect. Eng. and Comput. Sci. Massachusetts Institute of TechnologyCambridgeMA (2000).
  15. R. S. Muller, T. I. Kamins, Device Electronics for Integrated Circuits (Wiley, 1986) pp. 218-269.
  16. T. J. King, K. C. Saraswat, "Low-temperature $(\leq 550^{\circ}{\rm C})$ fabrication of poly-Si thin-film transistors," IEEE Electron Devices Lett. 13, 309-311 (1992).
  17. J. Sune, P. Olivo, B. Ricco, "Quantum-mechanical modeling of accumulation layers in MOS structure," IEEE Trans. Electron Devices 39, 1732-1739 (1992).
  18. L. F. Stokes, M. Chodorow, H. J. Shaw, "All-single-mode fiber resonator," Opt. Lett. 7, 288-290 (1982).
  19. K. Okamoto, Fundamentals of Optical Waveguides (Academic Press, 2000) pp. 125-171.
  20. G. P. Agrawal, Fiber-Optic Communication Systems (Wiley, 2002) pp. 193-195.
  21. L. Liao, D. R. Lim, A. M. Agarwal, X. Duan, K. K. Lee, L. C. Kimerling, "Optical transmission losses in polycrystalline silicon strip waveguides: Effects of waveguide dimensions, thermal treatment, hydrogen passivation, and wavelength," J. Electron. Mater. 29, 1380-1386 (2000).
  22. K. Okamoto, Fundamentals of Optical Waveguides (Academic Press, 2000) pp. 13-45.
  23. International Technology Roadmap for Semiconductors (2004)2004 Update Lithography http://www.itrs.net/Links/2004Update/2004_-07_-Lithography.pdf.
  24. International Technology Roadmap for Semiconductors (2004)2004 Update Front End Process http://www.itrs.net/Links/2004Update/2004_-06_-FEP.pdf.
  25. S. A. Clark, B. Culshaw, E. J. C. Dawney, I. E. Day, "Thermo-optic phase modulators in SIMOX material," Proc. SPIE (2000) pp. 16-24.
  26. Cyoptics Inc. (2008)Edge-Emitting DFB Laser Diode Chip at 1550 nm and DWDM Wavelengths for Use in Cooled CW Applications http://www.cyoptics.com/dynContentFolder/DS-295M.pdf.

Cited By

OSA is able to provide readers links to articles that cite this paper by participating in CrossRef's Cited-By Linking service. CrossRef includes content from more than 3000 publishers and societies. In addition to listing OSA journal articles that cite this paper, citing articles from other participating publishers will also be listed.

« Previous Article  |  Next Article »

OSA is a member of CrossRef.

CrossCheck Deposited