OSA's Digital Library

Optics Express

Optics Express

  • Editor: C. Martijn de Sterke
  • Vol. 16, Iss. 24 — Nov. 24, 2008
  • pp: 19695–19705

Impact of the contact metallization on the performance of photoconductive THz antennas

N. Vieweg, M. Mikulics, M. Scheller, K. Ezdi, R. Wilk, H.-W. Hübers, and M. Koch  »View Author Affiliations


Optics Express, Vol. 16, Issue 24, pp. 19695-19705 (2008)
http://dx.doi.org/10.1364/OE.16.019695


View Full Text Article

Enhanced HTML    Acrobat PDF (259 KB)





Browse Journals / Lookup Meetings

Browse by Journal and Year


   


Lookup Conference Papers

Close Browse Journals / Lookup Meetings

Article Tools

Share
Citations

Abstract

Both AuGe based alloys and Ti/Au metal layer stacks are widely used as ohmic metal contacts for photoconductive THz antennas made of low temperature grown GaAs. Here, we present the first systematic comparison between these two metallization types. A series of antennas of both kinds is excited by femtosecond laser pulses and by the emission from two diode lasers, i.e. we test the structures as pulsed THz emitters and as photomixers. In both cases, coherent and incoherent detection schemes are employed. We find that the power emitted from the antennas with AuGe metallization is 50% higher than that of antennas with a Ti/Au metal layer. From a comparison with a photomixer model we conclude that the higher output power results from a lower contact resistance of the AuGe contacts leading to an increased current flow. However, Ti/Au contacts have a higher thermal stability which might be advantageous if high system stability is called for.

© 2008 Optical Society of America

OCIS Codes
(130.4815) Integrated optics : Optical switching devices
(300.6495) Spectroscopy : Spectroscopy, teraherz

ToC Category:
Spectroscopy

History
Original Manuscript: October 6, 2008
Revised Manuscript: November 11, 2008
Manuscript Accepted: November 11, 2008
Published: November 13, 2008

Citation
N. Vieweg, M. Mikulics, M. Scheller, K. Ezdi, R. Wilk, H.W. Hübers, and M. Koch, "Impact of the contact metallization on the performance of photoconductive THz antennas," Opt. Express 16, 19695-19705 (2008)
http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-16-24-19695


Sort:  Author  |  Year  |  Journal  |  Reset  

References

  1. M. Tani, S. Matsuura, K. Sakai, and S. Nakashima, "Emission characteristics of photoconductive antennas based on low-temperature-grown GaAs and semi-insulating GaAs," Appl. Opt. 36, 7853-7859 (1997). [CrossRef]
  2. Y. Cai, I. Brener, J. Lopata, J. Wynn, L. Pfeiffer, and J. B. Stark, "Coherent terahertz radiation detection: Direct comparison between free-space electro-optic sampling and antenna detection," Appl. Phys. Lett. 73, 444-446 (1998). [CrossRef]
  3. S. Kono, M. Tani, P. Gu, and K. Sakai, "Detection of up to 20 THz with a low-temperature-grown GaAs photoconductive antenna gated with 15 fs light pulses," Appl. Phys. Lett. 77, 4104-4106 (2000). [CrossRef]
  4. Y. C. Shen, P. C. Upadhya, E. H. Linfield, H. E. Beere, and A. G. Davies, "Ultrabroadband terahertz radiation from low-temperature-grown GaAs photoconductive emitters," Appl. Phys. Lett. 83, 3117-3119 (2003). [CrossRef]
  5. K. Sakai, ed., Terahertz Optoelectronics (Springer, Berlin, 2005). [CrossRef]
  6. J. K. Luo, H. Thomas, D. V. Morgan, and D. Westwood, "Transport properties of GaAs layers grown by molecular beam epitaxy at low temperature and the effects of annealing," J. Appl. Phys. 79, 3622-3629 (1996). [CrossRef]
  7. K. A. McIntosh, K. B. Nichols, S. Verghese, and E. R. Brown, "Investigation of ultrashort photocarrier relaxation times in low-temperature-grown GaAs," Appl. Phys. Lett. 70, 354-356 (1997). [CrossRef]
  8. Y. Cai, I. Brener, J. Lopata, J. Wynn, L. Pfeiffer, and J. Federici, "Design and performance of singular electric field terahertz photoconducting antennas," Appl. Phys. Lett. 71, 2076-2078 (1997). [CrossRef]
  9. M. Mikulics, M. Marso, I. Cámara Mayorga, R. Güsten, S. Stanček, P. Kováč, S. Wu, X. Li, M. Khafizov, R. Sobolewski, E. A. Michael, R. Schieder, M. Wolter, D. Buca, A. Förster, P. Kordoš, and H. Lüth, "Photomixers fabricated on nitrogen-ion-implanted GaAs," Appl. Phys. Lett. 87, 41106-1 - 41106-3, (2005). [CrossRef]
  10. I. S. Gregory, C. Baker, W. R. Tribe, I. V. Bradley, M. J. Evans, E. H. Linfield, A. G. Davies, and M. Missous, "Optimization of Photomixers and Antennas for Continuous-Wave Terahertz Emission," IEEE J. Quantum Electron. 41, 717-728 (2005). [CrossRef]
  11. M. Mikulics, E. A. Michael, R. Schieder, J. Stutzki, R. Güsten, M. Marso, A. van der Hart, H. P. Bochem, H. Lüth, and P. Kordoš, "Traveling-wave photomixer with recessed interdigitated contacts on low-temperature-grown GaAs," Appl. Phys. Lett.  88, 41118-1 - 41118-3, (2006). [CrossRef]
  12. M. Mikulics, "Preparation and Optimization of Low-Temperature-Grown GaAs Photomixers," PhD thesis, RWTH Aachen and FZ Jülich, (2005).
  13. X-C. Zhang, "Generation and detection of terahertz electromagnetic pulses from semiconductor with femtosecond optics," J. Lumin. 66, 488-492 (1996). [CrossRef]
  14. S. Matsuura, M. Tani, and K. Sakai, "Generation of coherent terahertz radiation by photomixing in dipole photoconductive antennas," Appl. Phys. Lett. 70, 559-561 (1997). [CrossRef]
  15. M. Tonouchi, M. Yamashita, and M. Hangyo, "Terahertz radiation imaging of supercurrent distribution in vortex-penetrated YBa2Cu3O7-d thin film strips," J. Appl. Phys. 87, 7366-7375, (2000). [CrossRef]
  16. M. Hangyo, S. Tomozawa, Y. Murakami, M. Tonouchi, M. Tani, Z. Wang, K. Sakai, and S. Nakashima, "Terahertz radiation from superconducting YBa2Cu3O7-d thin films excited by femtosecond optical pulses," Appl. Phys. Lett. 69, 2122-2124, (1996). [CrossRef]
  17. S. M. Duffy, S. Verghese, K. A. McIntosh, A. Jackson, A. C. Gossard, and S. Matsuura, "Accurate Modeling of Dual Dipole and Slot Elements Used with Photomixers for Coherent Terahertz Output Power," IEEE Trans. Microwave Theory Tech. 49, 1032-1038 (2001). [CrossRef]
  18. M. Mikulics, X. Zheng, R. Adam, R. Sobolewski, and P. Kordos, "High-Speed Photoconductive Switch Based on Low-Temperature GaAs Transferred on SiO2-Si Substrate," IEEE Photon. Techn. Lett. 15, 528-530 (2003). [CrossRef]
  19. M. Mikulics, S. Wu, M. Marso, R. Adam, A. Förster, A. van der Hart, P. Kordos, H. Lüth, and R. Sobolewski, "Ultrafast and Highly Sensitive Photodetectors with Recessed Electrodes Fabricated on Low-Temperature-Grown GaAs," IEEE Photon. Technol. Lett. 18, 820-822 (2006). [CrossRef]
  20. K. A. McIntosh, E. R. Brown, K. B. Nichols, O. B. McMahon, W. F. DiNatale, and T. M. Lyszczarz, "Terahertz photomixing with diode lasers in low-temperature-grown GaAs, "Appl. Phys. Lett. 67, 3844-3846 (1995). [CrossRef]
  21. N. Zamdmer, Q. Hu, K.A. McIntosh, and S. Verghese, "Increase in response time of low-temperature-grown GaAs photoconductive switches at high voltage bias," Appl. Phys. Lett. 75, 2313-2315 (1999). [CrossRef]
  22. A. Krotkus, K. Bertulis, and R. Adomavicius, "Low temperature MBE grown GaAs for terahertz radiation application," Proc. 12th GAAS Symposium-Amsterdam (2004).
  23. E. D. Marshall and M. Murakami, "in Contacts to semiconductor," L. J. Brillson, ed., (Noyes Publication, New Jersey, 1993).
  24. A. G. Baca, F. Ren, J. C. Zolper, R. D. Briggs, and S. J. Pearton, "A survey of ohmic contacts to III-V compound semiconductors," Thin Solid Films 308-309, 599-606 (1997). [CrossRef]
  25. N. Newman, M. van Schilgaarde, T. Kendelwicz, M. D. Williams, and W. E. Spicer, "Electrical study of Schottky barriers on atomically clean GaAs(110) surfaces," Phys. Rev. B 33, 1146-1159 (1986). [CrossRef]
  26. J. B. Gunn, "The Discovery of Microwave Oscillation in Gallium Arsenide," IEEE Trans. Electron. Devices 23, 705-713 (1976). [CrossRef]
  27. N. Braslau, J. B. Gunn, and J. L. Staples, "Metal-Semiconductor Contacts For GaAs Bulk Effekt Devices," Solid-State Electron. 10, 381-383 (1967). [CrossRef]
  28. M. Bieler, M. Spitzer, H. Lecher, G. Hein, and U. Siegner, "Transfer of sub-5 ps electrical test pulses to coplanar and coaxial electronic devices," Electron. Lett. 38, 125-126 (2002). [CrossRef]
  29. W. M. Steffens, S. Heisig, U. D. Keil, and E. Oesterschulze, "Spatio-temporal imaging of voltage pulses with a laser-gated photoconductive sampling probe," Appl. Phys. B 69, 455-458 (1999). [CrossRef]
  30. J. Gyulai, J. W. Mayer, V. Rodriguez, A. Y. C. Yu, and H. J. Gopen, "Alloying Behavior of Au and Au-Ge on GaAs," J. Appl. Phys. 42, 3578-3585, (1971). [CrossRef]
  31. Y-C. Shih, M. Murakami, E. L. Wilkie, and A. C. Callegari, "Effects of interfacial microstructure on uniformity and thermal stability of AuNiGe ohmic contact to n-type GaAs," J. Appl. Phys. 62, 582-590, (1987). [CrossRef]
  32. M. Ogawa, "Alloying of Ni/Au-Ge films on GaAs," J. Appl. Phys. 51, 406-412 (1980). [CrossRef]
  33. H. Kuchling, Taschenbuch der Physik (Fachbuchverlag Leipzig, 2001).
  34. J. D. Speight and K. Cooper, "Interlayer diffusion phenomena in Ti-Au metallization on n-type GaAs at 250°-450°C," Thin Solid Films 25, S31-S37 (1975). [CrossRef]
  35. R. V. Ghita, C. Logofatu, C. Negrila, A. S. Manea, M. Cernea, and M. F. Lazarescu, "Studies of Ohmic Contact and Schottky Barriers on Au-Ge/GaAs and Au-Ti/GaAs," J. Optoelectron. Adv. Mater. 7, 3033-3037 (2005).
  36. G. Donzelli and A. Paccagnella, "Degradation Mechanism of Ti/Au and Ti/Pd/Au Gate Metallizations in GaAs MESFET’s," IEEE Trans. Electron Devices 34, 957-960 (1987). [CrossRef]
  37. S. Kasai, M. Watanabe, and T. Ouchi, "Improved Terahertz Wave Intensity in Photoconductive Antennas Formed of Annealed Low-Temperature Grown GaAs," Jpn. J. Appl. Phys. 46, 4163-4165 (2007). [CrossRef]
  38. H. Yamamoto, Z-Q. Fang, and D. C. Look, "Nonalloyed ohmic contacts on low-temperature molecular beam epitaxial GaAs: Influence of deep donor band," Appl. Phys. Lett,  57, 1537-1539 (1990). [CrossRef]
  39. M. Griebel, Ultraschnelle Ladungsträgerdynamik in LTG-GaAs und ErAs:GaAs-Übergittern-Grundlagen und Anwendungen, PhD thesis, MPI, Stuttgart, (2002).
  40. J. N. Randall, C. H. Yang, Y. C. Kao, and T. M. Moore, "Fabrication of electron beam defined ultrasmall Ohmic contacts for III-V semiconductors," J. Vac. Sci. Technol. B 7, 2007-2010 (1989). [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