Influence of the surface oxide content of a boron capping layer on UV photodetector performance

V. Mohammadi, R.W.E. van de Kruijs, Padmakumar Ramachandra Rao, J.M. Sturm, S. Nihtianov

Research output: Chapter in Book/Conference proceedings/Edited volumeConference contributionScientificpeer-review


This paper presents our latest results from the investigation of the surface oxide content in boron capped layers used as the entrance window in ultraviolet silicon (UV-Si) photodetectors. These photodetectors have been studied electrically and optically to define the correlation between oxide content and performance, i.e. the direct relationship between the amount of undesired surface oxide in the active region where the boron layer is deposited, and the detector stability to high UV exposure levels. The boron capping layers were deposited by either chemical or physical vapor based deposition techniques (CVD or PVD). Although these techniques provide photodetectors that are highly sensitive to UV radiation [1], the formation of surface oxide during deposition is a major concern, especially for stability. To analyze the oxide content, an XPS (X-ray photoelectron spectroscopy) analysis was performed on high-temperature (HT-CVD: 700 °C), low-temperature (LT-CVD: 400 °C), and room-temperature (RT-CVD: 25 °C) based pure boron (PureB) photodetectors. An inverse relationship between deposition temperature and oxide content was noticed. While the HT-CVD based photodetectors were found to contain 30% of oxide in its active region, this amount drops to less than 10% for LT-CVD, and to a few percent for RT-PVD based process.
Original languageEnglish
Title of host publication2015 9th International Conference on Sensing Technology (ICST)
Place of PublicationPiscataway, NJ
Number of pages5
ISBN (Electronic)978-1-4799-6314-0
Publication statusPublished - 24 Mar 2016
Event2015 9th International Conference on Sensing Technology - Auckland, New Zealand
Duration: 8 Dec 201510 Dec 2015


Conference2015 9th International Conference on Sensing Technology
Abbreviated titleICST
Country/TerritoryNew Zealand
Internet address


  • Pure-boron layer
  • UV photodetectors
  • EUV radiation CVD
  • PVD
  • XPS
  • surface oxide


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