Specific Process Knowledge/Doping: Difference between revisions

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==Doping results==

Revision as of 12:58, 3 December 2015

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Doping your wafer

This page is about doping your wafer or making a thin film layer doped with boron, phosphorous or Germanium. The links below direct you to various doping results achieved by the use of different processes and heat treatments.

  • Dope with Phosphorous - Doping Silicon wafers with phosphorous by thermal predeposition and drive-in
  • Dope with Boron - Doping Silicon wafers with boron by thermal predeposition and drive-in
  • Furnace LPCVD PolySilicon - Deposition of PolySi doped with boron or phosphorous
  • PECVD - Making boron glass (BSG), phosphorous glass (PSG), boron-phosphorous glass PBSG or germanium doped glass
  • Ion implantation


Comparison of different doping processes

Phosphorous predep Boron predep PECVD doped thin film Doped Poly Si Ion implantation
Generel description Dopants introduced by diffusion from gas-phase (POCl3). A thin phosphorous glass is formed on the substrate and phosphorous atoms are driven in. The phosphorous glass is afterward removed by a short BHF etch. Often further annealing is desired in order to redistribute the dopants in the material. This is done at 800°C - 1150°C in either high temperature annealing furnaces or by rapid thermal annealing. Dopants introduced by diffusion from solid source wafers containing B2O3. A boron glass is formed on the substrate and boron atoms are driven in. The boron glass is afterward removed by a low temperature oxidation process (1 hour at 800°C-900°C) in the boron drive in furnace (A1) followed by a BHF etch. Often further annealing is desired in order to redistribute the dopants in the material. This is done at 800°C - 1150°C in either high temperature annealing furnaces or by rapid thermal annealing. Deposition of doped thin film (oxides or nitrides). A high temperature step to drive in and redistribute the dopants in the material is required. This is typically done at 800°C - 1150°C in either high temperature annealing furnaces (C1 or C3) or by rapid thermal annealing. The doped glass can afterwards be removed in a BHF etch. Dopants introduced by in-situ doping of poly/amorphous Si. In some cases you need a high temperature step to redistribute the dopants in the material and alter the crystallinity. This is typically done at 800°C - 1150°C in either high temperature annealing furnaces (C1 or C3) or by rapid thermal annealing. Dopant ions are implanted into the substrate by a high-energy ion beam. Contrary the other doping techniques the doping concentration has a peak inside the substrate when introduced by ion-implantation. Ion implantation cannot be done at Danchip but IBS (Ion Beam Services) offers ion-beam implantation as a service. See more at the homepage of IBS: http://www.ion-beam-services.com/about_us.htm. When wafers return from Ion implantation they need a clean before entering the cleanroom. Activation and redistribution of the dopants is required and is done by a high temperature anneal (600°C-1000°C) in the high temperature furnaces or by rapid thermal anneal.
Process Temperature
  • 900°C - 1150°C
  • 1050°C - 1125°C
  • 300°C
  • 560°C - 620°C
  • Room temperature
Dopant
  • Phosporous (POCl3)
  • Boron (solid source wafers containing B2O3)
  • Phosphorous (PH3)
  • Boron (B2H6)
  • Germanium (GeH4)
  • Phosphorous (PH3)
  • Boron (B2H6 or BCl3)
  • See more information at IBS.
Substrate size
  • 100 mm wafers
  • 50 mm wafers
  • 100 mm wafers
  • 50 mm wafers
  • small samples
  • 50 mm wafers
  • 100 mm wafers
  • 150 mm wafers
  • 100 mm wafers (Boron and Phosphorous)
  • 150 mm wafers (only Boron)
  • See more information at IBS.
Allowed materials
  • Silicon
  • Poly/amorphous silicon
  • Oxide
  • Nitride
  • Silicon
  • Poly/amorphous silicon
  • Oxide
  • Nitride
  • Silicon
  • Poly/amorphous silicon
  • Oxide
  • Nitride
  • Silicon
  • Poly/amorphous silicon
  • Oxide
  • Nitride
  • See more information at IBS.