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Optics Express

Optics Express

  • Editor: Andrew M. Weiner
  • Vol. 22, Iss. 7 — Apr. 7, 2014
  • pp: 7458–7464

Low temperature Al2O3 surface passivation for carrier-injection SiGe optical modulator

Younghyun Kim, Jaehoon Han, Mitsuru Takenaka, and Shinichi Takagi  »View Author Affiliations

Optics Express, Vol. 22, Issue 7, pp. 7458-7464 (2014)

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Surface passivation by Al2O3 deposited by atomic layer deposition (ALD) at 200 °C is examined to suppress surface recombination for carrier-injection SiGe optical modulators. We have investigated the interface trap densities at SiO2/Si and Al2O3/Si interfaces formed by plasma enhanced chemical vapor deposition (PECVD) and ALD, respectively. By evaluating metal-oxide-semiconductor (MOS) capacitors formed on Si surfaces after dry etching, we found that the interface trap density of Al2O3 passivated surface is more than one order of magnitude less than that of SiO2 passivated one. As a result, the modulation efficiency is improved by 1.3 by inserting Al2O3 layer prior to SiO2 deposition by PECVD owing to superior interface between Al2O3 and Si. The Al2O3 passivated device exhibits comparable modulation efficiency to a thermally-grown SiO2 passivated one formed by dry oxidation. Hence, the ALD Al2O3 passivation is effective to passivate SiGe optical modulators for which low temperature processes are required.

© 2014 Optical Society of America

OCIS Codes
(130.3120) Integrated optics : Integrated optics devices
(250.7360) Optoelectronics : Waveguide modulators

ToC Category:

Original Manuscript: January 21, 2014
Revised Manuscript: March 12, 2014
Manuscript Accepted: March 18, 2014
Published: March 24, 2014

Younghyun Kim, Jaehoon Han, Mitsuru Takenaka, and Shinichi Takagi, "Low temperature Al2O3 surface passivation for carrier-injection SiGe optical modulator," Opt. Express 22, 7458-7464 (2014)

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  1. G. T. Reed, G. Mashanovich, F. Y. Gardes, D. J. Thomson, “Silicon optical modulators,” Nat. Photonics 4(8), 518–526 (2010). [CrossRef]
  2. R. A. Soref, B. R. Bennett, “Electrooptical Effects in Silicon,” IEEE J Quantum Electron. 23(1), 123–129 (1987). [CrossRef]
  3. Q. Xu, B. Schmidt, S. Pradhan, M. Lipson, “Micrometre-scale silicon electro-optic modulator,” Nature 435(7040), 325–327 (2005). [CrossRef] [PubMed]
  4. Q. Xu, S. Manipatruni, B. Schmidt, J. Shakya, M. Lipson, “12.5 Gbit/s carrier-injection-based silicon micro-ring silicon modulators,” Opt. Express 15(2), 430–436 (2007). [CrossRef] [PubMed]
  5. W. M. J. Green, M. J. Rooks, L. Sekaric, Y. A. Vlasov, “Ultra-compact, low RF power, 10 Gb/s silicon Mach-Zehnder modulator,” Opt. Express 15(25), 17106–17113 (2007). [CrossRef] [PubMed]
  6. S. Akiyama, T. Baba, M. Imai, T. Akagawa, M. Takahashi, N. Hirayama, H. Takahashi, Y. Noguchi, H. Okayama, T. Horikawa, T. Usuki, “12.5-Gb/s operation with 0.29-V·cm V(π)L using silicon Mach-Zehnder modulator based-on forward-biased pin diode,” Opt. Express 20(3), 2911–2923 (2012). [CrossRef] [PubMed]
  7. L. Liao, A. Liu, D. Rubin, J. Basak, Y. Chetrit, H. Nguyen, R. Cohen, N. Izhaky, M. Paniccia, “40 Gbit/s silicon optical modulator for high-speed applications,” Electron. Lett. 43, 51–52 (2009).
  8. D. J. Thomson, F. Y. Gardes, Y. Hu, G. Mashanovich, M. Fournier, P. Grosse, J. M. Fedeli, G. T. Reed, “High contrast 40Gbit/s optical modulation in silicon,” Opt. Express 19(12), 11507–11516 (2011). [CrossRef] [PubMed]
  9. F. Y. Gardes, D. J. Thomson, N. G. Emerson, G. T. Reed, “40 Gb/s silicon photonics modulator for TE and TM polarisations,” Opt. Express 19(12), 11804–11814 (2011). [CrossRef] [PubMed]
  10. T. Baehr-Jones, R. Ding, Y. Liu, A. Ayazi, T. Pinguet, N. C. Harris, M. Streshinsky, P. Lee, Y. Zhang, A. E.-J. Lim, T.-Y. Liow, S. H.-G. Teo, G.-Q. Lo, M. Hochberg, “Ultralow drive voltage silicon traveling-wave modulator,” Opt. Express 20(11), 12014–12020 (2012). [CrossRef] [PubMed]
  11. J. Ding, R. Ji, L. Zhang, L. Yang, “Electro-optical response analysis of a 40 Gb/s silicon Mach-Zehnder optical modulator,” J. Lightwave Technol. 31(14), 2434–2440 (2013). [CrossRef]
  12. M. Streshinsky, A. Ayazi, Z. Xuan, A. E.-J. Lim, G.-Q. Lo, T. Baehr-Jones, M. Hochberg, “Highly linear silicon traveling wave Mach-Zehnder carrier depletion modulator based on differential drive,” Opt. Express 21(3), 3818–3825 (2013). [CrossRef] [PubMed]
  13. M. Streshinsky, R. Ding, Y. Liu, A. Novack, Y. Yang, Y. Ma, X. Tu, E. K. Chee, A. E. Lim, P. G. Lo, T. Baehr-Jones, M. Hochberg, “Low power 50 Gb/s silicon traveling wave Mach-Zehnder modulator near 1300 nm,” Opt. Express 21(25), 30350–30357 (2013). [CrossRef] [PubMed]
  14. L. Yang, J. F. Ding, “High-Speed Silicon Mach-Zehnder Optical Modulator With Large Optical Bandwidth,” J. Lightwave Technol. 32(5), 966–970 (2014). [CrossRef]
  15. A. S. 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(6975), 615–618 (2004). [CrossRef] [PubMed]
  16. M. Takenaka, S. Takagi, “Strain Engineering of Plasma Dispersion Effect for SiGe Optical Modulators,” IEEE J. Quantum Electron. 48(1), 8–16 (2012). [CrossRef]
  17. J. Han, R. Zhang, T. Osada, M. Hata, M. Takenaka, and S. Takagi, “Improvement of SiGe MOS interfaces by plasma post-nitridation for SiGe high-k MOS optical modulators, “. 2012 IEEE International Conference on Group IV Photonics.
  18. Y. Kim, M. Yokoyama, N. Taoka, M. Takenaka, S. Takagi, “Ge-rich SiGe-on-insulator for waveguide optical modulator application fabricated by Ge condensation and SiGe regrowth,” Opt. Express 21(17), 19615–19623 (2013). [CrossRef] [PubMed]
  19. Y. Kim, M. Takenaka, and S. Takagi, “Numerical analysis of strained SiGe-based carrier-injection optical modulators,” 2012 IEEE International Conference on Group IV Photonics. [CrossRef]
  20. Y. Kim, M. Takenaka, T. Osada, M. Hata, and S. Takagi, “Strain-induced enhancement of plasma dispersion effect and free-carrier absorption in SiGe optical modulators,” eprint http:// arXiv:1304.1229 .
  21. G. R. Zhou, M. W. Geis, S. J. Spector, F. Gan, M. E. Grein, R. T. Schulein, J. S. Orcutt, J. U. Yoon, D. M. Lennon, T. M. Lyszczarz, E. P. Ippen, F. X. Käertner, “Effect of carrier lifetime on forward-biased silicon Mach-Zehnder modulators,” Opt. Express 16(8), 5218–5226 (2008). [CrossRef] [PubMed]
  22. S. Park, K. Yamada, T. Tsuchizawa, T. Watanabe, H. Shinojima, H. Nishi, R. Kou, S. Itabashi, “Influence of carrier lifetime on performance of silicon p-i-n variable optical attenuators fabricated on submicrometer rib waveguides,” Opt. Express 18(11), 11282–11291 (2010). [CrossRef] [PubMed]
  23. R. Hull, J. C. Bean, D. J. Werder, R. E. Leibenguth, “In situ observations of misfit dislocation propagation in GexSi1−x/Si(100) heterostructures,” Appl. Phys. Lett. 52(19), 1605 (1988). [CrossRef]
  24. Eh. Nicollia, A. Goetzber, “Si-SiO2 Interface - Electrical Properties as Determined by Metal-Insulator-Silicon Conductance Technique,” AT&T Tech. J. 46, 1055 -& (1967).

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