Germanium p-i-n photodiode on silicon for integrated photonic applications

Jay Mathews, Radek Roucka, Change Weng, John Tolle, Jose Menendez, John Kouvetakis

Research output: Chapter in Book/Report/Conference proceedingConference contribution

2 Scopus citations


The application of silicon photonic technologies to optical telecommunications requires the development of near-infrared detectors monolithically integrated to the Si platform. Recently, efforts in this area have focused on developing detectors from pure-Ge grown epitaxially on Si substrates. Much effort has been spent on achieving growth of high quality, relaxed Ge films for device structures, but low temperature growth and processing compatible with complementary-metal-oxide-semiconductor (CMOS) technology has yet to be achieved. In this paper, we report on p-i-n heterostructure photodiodes fabricated from Ge films grown directly on Si substrates using a low temperature chemical vapor deposition (CVD) process. The heterostructures were grown on arsenic-doped (n-type) Si(100) with resistivity 0.003 Ω-cm. A 350nm thick layer of intrinsic Ge was deposited first as the active region, followed by 100nm of boron-doped (p-type) Ge. Ohmic contacts were formed by evaporation of Cr and Au. The diodes were characterized with respect to their dark currents and responsivities in the near-IR. For a 60-μm-diameter device at room temperature, the dark current densities were on the order of 10-2 A/cm2 and 103 A/cm 2 at -1V and 1V, respectively, the "turn-on" voltage was found to be 0.26 V, and the ideality factor n was found to be 1.2. The external quantum efficiency of the devices was measured at room temperature over the range 1-1.8 μm. The responsivities at 1.3 and 1.55 μm were found to be 0.26 and 0.11, respectively.

Original languageEnglish (US)
Title of host publicationSilicon Photonics V
StatePublished - May 6 2010
EventSilicon Photonics V - San Francisco, CA, United States
Duration: Jan 24 2010Jan 27 2010

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X


OtherSilicon Photonics V
Country/TerritoryUnited States
CitySan Francisco, CA


  • Detectors
  • Diode
  • Germanium
  • Heterostructure
  • Integration
  • Optoelectronics
  • Photonics
  • Silicon

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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