Specific Process Knowledge/Doping

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Doping your wafer

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

• Doping with Phosphorous using high temperature furnaces - Doping silicon wafers with phosphorus by thermal pre-deposition and drive-in
• Doping with Boron using high temperature furnaces - Doping silicon wafers with boron by thermal pre-deposition and drive-in
• Oxide mask thickness - Required oxide mask thickness for pre deposition and diffusion
• Doping using LPCVD PolySilicon Furnaces - Deposition of Poly-Si or amorphous Si doped with boron or phosphorus
• Doping using PECVD - Making boron glass (BSG), phosphorous glass (PSG) or boron-phosphorus glass (PBSG)
• Ion implantation (not possible at Nanolab)

Comparison of different doping processes

	Phosphorous predep	Boron predep	PECVD doped thin film	Doped poly/amorphous 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 Nanolab 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)	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.