Interdigitated Ge p-i-n photodetectors fabricated on a Si substrate using graded SiGe buffer layers

Jungwoo Oh, Joe C. Campbell, Shawn G. Thomas, Sushil Bharatan, Rainer Thoma, Craig Jasper, Robert E. Jones, Tom E. Zirkle

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Abstract

We report an interdigitated p-i-n photodetector fabricated on a 1-μm-thick Ge epitaxial layer grown on a Si substrate using a 10-μm-thick graded SiGe buffer layer. A growth rate of 45 Å/s∼60 Å/s was achieved using low-energy plasma enhanced chemical vapor deposition. The Ge epitaxial layer had a threading dislocation density of 105 cm-2 and a rms surface roughness of 3.28 nm. The 3-dB bandwidth and the external quantum efficiency were measured on a photodetector having 1-μm finger width and 2-μm spacing the a 25 × 28 μm2 active area. At a wavelength of 1.3 μm, the bandwidth was 2.2, 3.5, and 3.8 GHz at bias voltages of -1, -3, and -5 V, respectively. The dark current was 3.2 and 5.0 μA at -3 and -5V, respectively. This photodetector exhibited an external quantum efficiency of 49% at a wavelength of 1.3 μm.

Original languageEnglish
Pages (from-to)1238-1241
Number of pages4
JournalIEEE Journal of Quantum Electronics
Volume38
Issue number9
DOIs
Publication statusPublished - 2002 Sep 1

All Science Journal Classification (ASJC) codes

  • Atomic and Molecular Physics, and Optics
  • Condensed Matter Physics
  • Electrical and Electronic Engineering

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    Oh, J., Campbell, J. C., Thomas, S. G., Bharatan, S., Thoma, R., Jasper, C., Jones, R. E., & Zirkle, T. E. (2002). Interdigitated Ge p-i-n photodetectors fabricated on a Si substrate using graded SiGe buffer layers. IEEE Journal of Quantum Electronics, 38(9), 1238-1241. https://doi.org/10.1109/JQE.2002.802165