Growth of AlGaN on silicon substrates: A novel way to make back-illuminated ultraviolet photodetectors

Ryan P McClintock, Manijeh Razeghi

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

4 Scopus citations


AlGaN, with its tunable wide-bandgap is a good choice for the realization of ultraviolet photodetectors. AlGaN films tend to be grown on foreign substrates such as sapphire, which is the most common choice for back-illuminated devices. However, even ultraviolet opaque substrates like silicon holds promise because, silicon can be removed by chemical treatment to allow back-illumination,1 and it is a very low-cost substrate which is available in large diameters up to 300 mm. However, Implementation of silicon as the solar-blind PD substrates requires overcoming the lattice-mismatch (17%) with the AlxGa1-xN that leads to high density of dislocation and crack-initiating stress. In this talk, we report the growth of thick crack-free AlGaN films on (111) silicon substrates through the use of a substrate patterning and mask-less selective area regrowth. This technique is critical as it decouples the epilayers and the substrate and allows for crack-free growth; however, the masking also helps to reduce the dislocation density by inclining the growth direction and encouraging dislocations to annihilate. A back-illuminated p-i-n PD structure is subsequently grown on this high quality template layer. After processing and hybridizing the device we use a chemical process to selectively remove the silicon substrate. This removal has minimal effect on the device, but it removes the UV-opaque silicon and allows back-illumination of the photodetector. We report our latest results of back-illuminated solar-blind photodetectors growth on silicon.

Original languageEnglish (US)
Title of host publicationOptical Sensing, Imaging, and Photon Counting
Subtitle of host publicationNanostructured Devices and Applications
EditorsGail J. Brown, Manijeh Razeghi, Dorota S. Temple
ISBN (Electronic)9781628417210
StatePublished - Jan 1 2015
EventOptical Sensing, Imaging, and Photon Counting - San Diego, United States
Duration: Aug 11 2015Aug 13 2015


OtherOptical Sensing, Imaging, and Photon Counting
Country/TerritoryUnited States
CitySan Diego


  • AlGaN
  • AlN
  • Photodetector
  • Silicon
  • Substrate Removal
  • Ultraviolet

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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