Reduction of boron diffusion in silicon-germanium by fluorine implantation
Reduction of boron diffusion in silicon-germanium by fluorine implantation
This paper investigates the effect of a 185 keV, 2.3×1015cm-2 F+ implant on boron thermal diffusion and boron transient enhanced diffusion (TED) in SiGe by characterising the diffusion of a boron marker layer in samples with and without a 288 keV, 6×1013cm-2 P+ implant. In samples implanted with F+ only, the fluorine suppresses boron thermal diffusion by 58%. In samples given both P+ and F+ implants, the fluorine completely eliminates boron transient enhanced diffusion caused by the P+ implant and also significantly reduces boron thermal diffusion. SIMS profiles after anneal show a fluorine concentration in the SiGe layer that is approximately 8× higher than after implant, indicating that fluorine accumulates in the SiGe layer during anneal. A comparison with fluorine profiles in comparable silicon samples also shows that the fluorine concentration after anneal is dramatically higher in SiGe samples than in Si samples. This accumulation of fluorine in the SiGe layer during anneal will have major benefits for boron diffusion suppression in devices like SiGe HBTs, where boron must be kept within the SiGe layer.
silicon, germanium, fluorine, diffusion, boron
535-537
El Mubarek, H.A.W.
08195505-5e00-40a6-bc9f-ebbf2a2fbf63
Ashburn, P.
68cef6b7-205b-47aa-9efb-f1f09f5c1038
2004
El Mubarek, H.A.W.
08195505-5e00-40a6-bc9f-ebbf2a2fbf63
Ashburn, P.
68cef6b7-205b-47aa-9efb-f1f09f5c1038
El Mubarek, H.A.W. and Ashburn, P.
(2004)
Reduction of boron diffusion in silicon-germanium by fluorine implantation.
IEEE Electron Device Letters, 25 (8), .
Abstract
This paper investigates the effect of a 185 keV, 2.3×1015cm-2 F+ implant on boron thermal diffusion and boron transient enhanced diffusion (TED) in SiGe by characterising the diffusion of a boron marker layer in samples with and without a 288 keV, 6×1013cm-2 P+ implant. In samples implanted with F+ only, the fluorine suppresses boron thermal diffusion by 58%. In samples given both P+ and F+ implants, the fluorine completely eliminates boron transient enhanced diffusion caused by the P+ implant and also significantly reduces boron thermal diffusion. SIMS profiles after anneal show a fluorine concentration in the SiGe layer that is approximately 8× higher than after implant, indicating that fluorine accumulates in the SiGe layer during anneal. A comparison with fluorine profiles in comparable silicon samples also shows that the fluorine concentration after anneal is dramatically higher in SiGe samples than in Si samples. This accumulation of fluorine in the SiGe layer during anneal will have major benefits for boron diffusion suppression in devices like SiGe HBTs, where boron must be kept within the SiGe layer.
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2004_Huda_F_in_SiGe.pdf
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Published date: 2004
Keywords:
silicon, germanium, fluorine, diffusion, boron
Organisations:
Nanoelectronics and Nanotechnology
Identifiers
Local EPrints ID: 260247
URI: http://eprints.soton.ac.uk/id/eprint/260247
ISSN: 0741-3106
PURE UUID: 128c4b73-d25e-4d05-a1b8-d031c2aa36eb
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Date deposited: 10 Jan 2005
Last modified: 14 Mar 2024 06:35
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Author:
H.A.W. El Mubarek
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