High effective gummel number of CVD boron layers in ultrashallow p +n diode configurations

Francesco Sarubbi*, Lis K. Nanver, Tom L M Scholtes

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

46 Citations (Scopus)


Deposited boron layers fabricated by exposing silicon to diborane (B 2H6) gas in an atmospheric-pressure chemical vapor deposition reactor are investigated with respect to their electrical properties. At the applied temperatures from 500 °C to 700 °C, the deposition forms a nanometer-thick layer stack of amorphous boron (α-B) and boronsilicon compound (BxSiy), whereas the crystalline Si substrate is p-doped to depths below 10 nm, depending on the temperature and exposure time. The as-deposited layers can be used to fabricate high-quality p+n diodes with low series resistance and low saturation current values that are comparable with those of conventional deep p+ junctions. By investigating p-n-p structures with p+ B-deposited emitters, it is shown that the presence of the α-B layer increases the effective Gummel number of the diffused emitter up to about a factor of 60. The α-B layer is also demonstrated to be a stable and controllable supply of B for the formation of deep p-type regions by thermal drive-in.

Original languageEnglish
Article number5447662
Pages (from-to)1269-1278
Number of pages10
JournalIEEE Transactions on Electron Devices
Issue number6
Publication statusPublished - 1 Jun 2010
Externally publishedYes


  • Boron (B)
  • Chemical vapor deposition (CVD)
  • Diborane(BH)
  • Doping
  • Emitter
  • Gummel number
  • P-n-p bipolar transistor
  • Pn diode
  • Solid-phase diffusion
  • Transient-enhanced diffusion (TED)
  • Ultrashallow junctions

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