OSA's Digital Library

Optics Express

Optics Express

  • Editor: C. Martijn de Sterke
  • Vol. 20, Iss. 8 — Apr. 9, 2012
  • pp: 8718–8725

Dark current reduction of Ge photodetector by GeO2 surface passivation and gas-phase doping

Mitsuru Takenaka, Kiyohito Morii, Masakazu Sugiyama, Yoshiaki Nakano, and Shinichi Takagi  »View Author Affiliations

Optics Express, Vol. 20, Issue 8, pp. 8718-8725 (2012)

View Full Text Article

Enhanced HTML    Acrobat PDF (944 KB)

Browse Journals / Lookup Meetings

Browse by Journal and Year


Lookup Conference Papers

Close Browse Journals / Lookup Meetings

Article Tools



We have investigated the dark current of a germanium (Ge) photodetector (PD) with a GeO2 surface passivation layer and a gas-phase-doped n+/p junction. The gas-phase-doped PN diodes exhibited a dark current of approximately two orders of magnitude lower than that of the diodes formed by a conventional ion implantation process, indicating that gas-phase doping is suitable for low-damage PN junction formation. The bulk leakage (Jbulk) and surface leakage (Jsurf) components of the dark current were also investigated. We have found that GeO2 surface passivation can effectively suppress the dark current of a Ge PD in conjunction with gas-phase doping, and we have obtained extremely low values of Jbulk of 0.032 mA/cm2 and Jsurf of 0.27 μA/cm.

© 2012 OSA

OCIS Codes
(040.5160) Detectors : Photodetectors
(060.4510) Fiber optics and optical communications : Optical communications
(250.0250) Optoelectronics : Optoelectronics

ToC Category:

Original Manuscript: February 8, 2012
Revised Manuscript: March 21, 2012
Manuscript Accepted: March 27, 2012
Published: March 30, 2012

Mitsuru Takenaka, Kiyohito Morii, Masakazu Sugiyama, Yoshiaki Nakano, and Shinichi Takagi, "Dark current reduction of Ge photodetector by GeO2 surface passivation and gas-phase doping," Opt. Express 20, 8718-8725 (2012)

Sort:  Author  |  Year  |  Journal  |  Reset  


  1. J. Michel, J. Liu, and L. C. Kimerling, “High-performance Ge-on-Si photodetectors,” Nat. Photonics4(8), 527–534 (2010). [CrossRef]
  2. S. Luryi, A. Kastalsky, and J. C. Bean, “New infrared detector on a silicon chip,” IEEE Trans. Electron. Dev.31(9), 1135–1139 (1984). [CrossRef]
  3. S. B. Samavedam, M. T. Currie, T. A. Langdo, and E. A. Fitzgerald, “High-quality germanium photodiodes integrated on silicon substrates using optimized relaxed graded buffers,” Appl. Phys. Lett.73(15), 2125–2127 (1998). [CrossRef]
  4. H. C. Luan, D. R. Lim, K. K. Lee, K. M. Chen, J. G. Sandland, K. Wada, and L. C. Kimerling, “High-quality Ge epilayers on Si with low threading-dislocation densities,” Appl. Phys. Lett.75(19), 2909–2911 (1999). [CrossRef]
  5. J. Osmond, G. Isella, D. Chrastina, R. Kaufmann, M. Acciarri, and H. von Kanel, “Ultralow dark current Ge/Si(100) photodiodes with low thermal budget,” Appl. Phys. Lett.94(20), 201106 (2009). [CrossRef]
  6. H. Y. Yu, S. Ren, W. S. Jung, A. K. Okyay, D. A. B. Miller, and K. C. Saraswat, “High-efficiency p-i-n photodetectors on selective-area-grown Ge for monolithic integration,” IEEE Electron Device Lett.30(11), 1161–1163 (2009). [CrossRef]
  7. T. H. Loh, H. S. Nguyen, R. Murthy, M. B. Yu, W. Y. Loh, G. Q. Lo, N. Balasubramanian, D. L. Kwong, J. Wang, and S. J. Lee, “Selective epitaxial germanium on silicon-on-insulator high speed photodetectors using low-temperature ultrathin Si0.8Ge0.2 buffer,” Appl. Phys. Lett.91(7), 073503 (2007). [CrossRef]
  8. L. Colace, P. Ferrara, G. Assanto, D. Fulgoni, and L. Nash, “Low dark-current germanium-on-silicon near-infrared detectors,” IEEE Photon. Technol. Lett.19(22), 1813–1815 (2007). [CrossRef]
  9. D. Ahn, C. Y. Hong, J. Liu, W. Giziewicz, M. Beals, L. C. Kimerling, J. Michel, J. Chen, and F. X. Kärtner, “High performance, waveguide integrated Ge photodetectors,” Opt. Express15(7), 3916–3921 (2007). [CrossRef] [PubMed]
  10. S. Park, T. Tsuchizawa, T. Watanabe, H. Shinojima, H. Nishi, K. Yamada, Y. Ishikawa, K. Wada, and S. Itabashi, “Monolithic integration and synchronous operation of germanium photodetectors and silicon variable optical attenuators,” Opt. Express18(8), 8412–8421 (2010). [CrossRef] [PubMed]
  11. T. Yin, R. Cohen, M. M. Morse, G. Sarid, Y. Chetrit, D. Rubin, and M. J. Paniccia, “31 GHz Ge n-i-p waveguide photodetectors on Silicon-on-Insulator substrate,” Opt. Express15(21), 13965–13971 (2007). [CrossRef] [PubMed]
  12. K. W. Ang, T. Y. Liow, M. B. Yu, Q. Fang, J. Song, G. Q. Lo, and D. L. Kwong, “Low thermal budget monolithic integration of evanescent-coupled Ge-on-SOI photodetector on Si CMOS platform,” IEEE J. Sel. Top. Quantum Electron.16(1), 106–113 (2010). [CrossRef]
  13. S. Assefa, F. Xia, and Y. A. Vlasov, “Reinventing germanium avalanche photodetector for nanophotonic on-chip optical interconnects,” Nature464(7285), 80–84 (2010). [CrossRef] [PubMed]
  14. M. Beals, J. Michel, J. F. Liu, D. H. Ahn, D. Sparacin, R. Sun, C. Y. Hong, L. C. Kimerling, A. Pomerene, D. Carothers, J. Beattie, A. Kopa, A. Apsel, M. S. Rasras, D. M. Gill, S. S. Patel, K. Y. Tu, Y. K. Chen, and A. E. White, “Process flow innovations for photonic device integration in CMOS,” Proc. SPIE6898, 689804(2008). [CrossRef]
  15. Thorlabs Inc, http://www.thorlabs.com .
  16. H. Ando, H. Kanbe, T. Kimura, T. Yamaoka, and T. Kaneda, “Characteristics of germanium avalanche photodiodes in the wavelength region of 1-1.6 μm,” IEEE J. Quantum Electron.14(11), 804–809 (1978). [CrossRef]
  17. S. Kagawa, T. Kaneda, T. Mikawa, Y. Banba, and Y. Toyama, “Fully ion-implanted p+ -n germanium avalanche photodiodes,” Appl. Phys. Lett.38(6), 429–431 (1981). [CrossRef]
  18. C. O. Cui, K. Gopalakrishnan, P. B. Griffin, J. D. Plummer, and K. C. Saraswat, “Activation and diffusion studies of ion-implanted p and n dopants in germanium,” Appl. Phys. Lett.83(16), 3275–3277 (2003). [CrossRef]
  19. O. Fidaner, A. K. Okyay, J. E. Roth, R. K. Schaevitz, Y.-H. Kuo, K. C. Saraswat, J. S. Harris, and D. A. B. Miller, “Ge–SiGe quantum-well waveguide photodetectors on silicon for the near-infrared,” IEEE Photon. Technol. Lett.19(20), 1631–1633 (2007). [CrossRef]
  20. M. Takenaka, K. Morii, M. Sugiyama, Y. Nakano, and S. Takagi, “Gas phase doping of arsenic into (100), (110), and (111) germanium substrates using a metal–organic source,” Jpn. J. Appl. Phys.50, 010105 (2011). [CrossRef]
  21. H. Matsubara, T. Sasada, M. Takenaka, and S. Takagi, “Evidence of low interface trap density in GeO2/Ge metal-oxide-semiconductor structures fabricated by thermal oxidation,” Appl. Phys. Lett.93(3), 032104 (2008). [CrossRef]
  22. T. Sasada, Y. Nakakita, M. Takenaka, and S. Takagi, “Surface orientation dependence of interface properties of GeO2/Ge metal-oxide-semiconductor structures fabricated by thermal oxidation,” J. Appl. Phys.106(7), 073716 (2009). [CrossRef]
  23. N. D. Nguyen, E. Rosseel, S. Takeuchi, J. L. Everaert, L. Yang, J. Goossens, A. Moussa, T. Clarysse, O. Richard, H. Bender, S. Zaima, A. Sakai, R. Loo, J. C. Lin, W. Vandervorst, and M. Caymax, “Use of p- and n-type vapor phase doping and sub-melt laser anneal for extension junctions in sub-32 nm CMOS technology,” Thin Solid Films518(6), S48–S52 (2010). [CrossRef]
  24. K. Morii, T. Iwasaki, R. Nakane, M. Takenaka, and S. Takagi, “High-performance GeO2/Ge nMOSFETs with source/drain junctions formed by gas-phase doping,” IEEE Electron Device Lett.31(10), 1092–1094 (2010). [CrossRef]
  25. M. D. Jack and J. Y. M. Lee, “DLTS measurements of a germanium MIS interface,” J. Electron. Mater.10(3), 571–589 (1981). [CrossRef]
  26. E. E. Crisman, J. I. Lee, P. J. Stiles, and O. J. Gregory, “Characterisation of n-channel germanium mosfet with gate insulator formed by high-pressure thermal oxidation,” Electron. Lett.23(1), 8–10 (1987). [CrossRef]
  27. Y. Wang, Y. Z. Hu, and E. A. Irene, “Electron cyclotron resonance plasma and thermal oxidation mechanisms of germanium,” J. Vac. Sci. Technol. A12(4), 1309–1314 (1994). [CrossRef]
  28. V. Craciun, I. W. Boyd, B. Hutton, and D. Williams, “Characteristics of dielectric layers grown on Ge by low temperature vacuum ultraviolet-assisted oxidation,” Appl. Phys. Lett.75(9), 1261–1263 (1999). [CrossRef]
  29. R. S. Johnson, H. Niimi, and G. Lucovsky, “New approach for the fabrication of device-quality Ge/GeO2 /SiO2 interfaces using low temperature remote plasma processing,” J. Vac. Sci. Technol. A18(4), 1230–1233 (2000). [CrossRef]
  30. Y. Nakakita, R. Nakakne, T. Sasada, M. Takenaka, and S. Takagi, “Interface-controlled self-align source/drain Ge p-channel metal–oxide–semiconductor field-effect transistors fabricated using thermally oxidized GeO2 interfacial layers,” Jpn. J. Appl. Phys.50, 010109 (2011). [CrossRef]
  31. S. J. Koester, J. D. Schaub, G. Dehlinger, and J. O. Chu, “Germanium-on-SOI infrared detectors for integrated photonic applications,” IEEE J. Sel. Top. Quantum Electron.12(6), 1489–1502 (2006). [CrossRef]

Cited By

Alert me when this paper is cited

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