El Mubarek, Huda

Gandy, A.

Mubarek, H.A.W. El

English

In our previous work we have shown that F+ implantation eliminates transient enhanced diffusion (TED), and significantly reduce thermal diffusion of B in Si1-xGe¬x [1]. We proposed that the reduction in boron thermal diffusion is mainly due to the suppression of the local self-interstitial concentration by vacancy-fluorine clusters (FnVm) [1]. A recent theoretical study concluded that F+ codoping in Ge suppresses donor diffusion and deactivation by the production of FnVm clusters [2]. These publications indicate that vacancy-fluorine clusters play a significant role in minimising dopants diffusion in SiGe and Ge, a requirement which is necessary for the formation of ultra-shallow junctions in advanced CMOS devices. In order to understand fully the mechanisms governing the suppression of dopants diffusion, detailed studies are required in order to determine the morphology of F implantation-induced defects in SiGe. In this study, we present for the first time in the literature the observation of fluorine implantation induced defects in SiGe. Strained Si1-xGe¬x multi-layers were grown by low pressure chemical vapour deposition (LPCVD) on (100) Si wafers. The Ge content within the layers was 10%, 6%, and 3%, and the widths of the layers were 52nm, 44nm and 52nm, respectively. The multi-layer samples were implanted, at room temperature, with 185keV, 2.3x1015 F+ ions/cm2. The samples were then annealed by rapid thermal annealing in N2 for 30 seconds at either 950°C or 1000°C. Germanium and Fluorine profiles were obtained using secondary ion mass spectroscopy (SIMS). Transmission electron microscopy (TEM) was used to investigate the implantation induced defects. Bright-field electron micrographs were taken using kinematical diffraction conditions. The defects were identified by Fresnel contrast and analysis of a through-focal-series. Nanometre sized vacancy-type defects were detected in regions of relatively high F+ concentration, and are proposed to be FnVm clusters. A larger number of vacancy clusters were observed in Si1-xGe¬x compared to Si, which is possibly due to the lower formation energy of vacancies in Si1-xGe¬x, than in Si [3]. To the authors’ knowledge, this is the first time F+ implantation induced vacancy clusters have been identified by TEM in Si1-xGe¬x. [1] H. A. W. El Mubarek, M. Karunaratne, J. M. Bonar, G. D. Dilliway, Y. Wang, P. L. F. Hemment, A. F. Willoughby, P. Ashburn, “Effect of fluorine implantation dose on boron transient enhanced diffusion and boron thermal diffusion in SiGe”, IEEE Transactions on Electron Devices, vol. 52 (4), pp. 518-526, (2005). [2] Chroneos. A, Grimes. R. W, Bracht. H. “Fluorine codoping in germanium to suppress donor diffusion and deactivation”. Journal of Applied Physics 106 (2009) 063707. [3] Dalpian. G. M, Venezuela. P, da Silva Antônio J. R, Fazzio A. “Ab initio calculations of vacancies in SixGe1–x”. Applied Physics Letters 81, 3383 (2002)

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The University of Manchester ResearchDefects induced by F+ implantation in SiGe observed byTransmission Electron MicroscopyLink to publication record in Manchester Research ExplorerCitation for published version (APA):El Mubarek, H., Gandy, A., & Mubarek, H. A. W. E. (2010). Defects induced by F+ implantation in SiGe observedby Transmission Electron Microscopy. The European Materials Research Society EMRS Spring 2010, Strasbourg,France.Citing this paperPlease note that where the full-text provided on Manchester Research Explorer is the Author Accepted Manuscriptor Proof version this may differ from the final Published version. If citing, it is advised that you check and use thepublisher's definitive version.General rightsCopyright and moral rights for the publications made accessible in the Research Explorer are retained by theauthors and/or other copyright owners and it is a condition of accessing publications that users recognise andabide by the legal requirements associated with these rights.Takedown policyIf you believe that this document breaches copyright please refer to the University of Manchester’s TakedownProcedures [http://man.ac.uk/04Y6Bo] or contact uml.scholarlycommunications@manchester.ac.uk providingrelevant details, so we can investigate your claim.Download date:30. Jun. 2022Suppression of Phosphorus Diffusion in Silicon by Fluorine Co - implantationByDr Huda Abdel Wahab A. El MubarekHuda.elmubarek@manchester.ac.ukRoyal Academy of Engineering and EPSRC Research FellowAcknowledgments• University of Southampton • Royal Academy of Engineering and EPSRC: Fellowship• EPSRC: EPSRC GrantContents• Motivation• Experimental Procedure• Results – Effect of F+ Implantation on Phosphorus  Diffusion in Si– Fluorine Diffusion in Silicon– Fluorine and Phosphorus Implantation Damage in Silicon• Discussion• ConclusionsMotivation• Phosphorus diffuses Significantly in Si due to Transient Enhanced Diffusion (TED)• F+ implantation into Si1:• Eliminates B TED• Significantly reduces B thermal diffusion• No work to date on the effect of F +Implantation on Phosphorus diffusion in Si 1.H. A. W. El Mubarek, P. Ashburn, “Reduction of boron thermal diffusion and elimination of boron transient enhanced diffusion in silicon by high energy fluorine implantation”, Applied Physics Letters , vol. 83 (20), pp. 4134-4136 , (2003).Experimental Procedure(100) P type SiExperimental ProcedureF+ 185KeV, 9x1014or 2.3x1015ions/cm2(100) P type SiF Rp = 0.4µmExperimental ProcedureP+ 100KeV, 6x1013ions/cm2P Rp = 0.15µm(100) P type SiF Rp = 0.4µmExperimental Procedure• Samples diced 1cm×1cm Pieces• Rapid Thermal Annealing  in Nitrogen at 800°C , 900°C or 1000°C for 30 seconds • P an F profiles obtained by SIMS• Transmission Electron MicroscopyResultsEffect of  F+ implantation on P diffusion in Si at 800°C,30s in Nitrogen1.E+181.E+19Concentration (cm-3)P (no F) P (9e14F) P (2.3e15F)P as imp Phosphorus Profiles (800°C, 30s)F+ implantation eliminates Phosphorus diffusion at 800 °C1.E+170.0 0.1 0.2 0.3 0.4 0.5Depth (Microns)Concentration (cmEffect of F+ implantation on P diffusion in Si at 900°C,30s in Nitrogen1.E+181.E+19Concentration (cm-3)P as imp P(no F)P (9e14F)Phosphorus Profiles (900°C, 30s)1.E+170.0 0.1 0.2 0.3 0.4 0.5Depth (microns)Concentration (cmF+ implantation eliminates Phosphorus diffusion at 900 °CEffect of F+ implantation on P diffusion in Si at 1000°C,30s in Nitrogen1.E+181.E+19Concentration (cm-3)P as imp P(no F)P(2.3e15 F)P (9e14 F)Phosphorus Profiles (1000°C, 30s)1.E+170.0 0.1 0.2 0.3 0.4 0.5Depth (Microns)Concentration (cmF+ implantation eliminates Phosphorus diffusion at 100 0°CFluorine  Diffusion in Silicon1.E+181.E+191.E+20Concentration (cm-3)P   F (As implanted)F (800°C, 30s)185KeV 9×1014cm -2 F+ diffusion in Si1.E+161.E+170.0 0.2 0.4 0.6 0.8 1.0Depth (Microns)Concentration (cm1.E+181.E+191.E+20Concentration (cm-3)P   F (As implanted)F (800°C, 30s)F (900°C.30s)185KeV 9×1014cm -2 F+ diffusion in Si1.E+161.E+170.0 0.2 0.4 0.6 0.8 1.0Depth (Microns)Concentration (cm1.E+181.E+191.E+20Concentration (cm-3)P   F (As implanted)F (800°C, 30s)F (900°C.30s)F (1000°C,30s)185KeV 9×1014cm -2 F+ diffusion in Si1.E+161.E+170.0 0.2 0.4 0.6 0.8 1.0Depth (Microns)Concentration (cm1.E+181.E+191.E+20Concentration (cm-3)P  F (As implanted)  F (800°C,30s) 185KeV 2.3×1015cm -2 F+ diffusion in Si1.E+161.E+170.0 0.2 0.4 0.6 0.8 1.0Depth (Microns)Concentration (cm1.E+181.E+191.E+20Concentration (cm-3)P  F (As implanted)  F (800°C,30s) F (900°C,30s)185KeV 2.3×1015cm -2 F+ diffusion in Si1.E+161.E+170.0 0.2 0.4 0.6 0.8 1.0Depth (Microns)Concentration (cm1.E+181.E+191.E+20Concentration (cm-3)P  F (As implanted)  F (800°C,30s) F (900°C,30s)F (1000°C,30s)185KeV 2.3×1015cm -2 F+ diffusion in Si1.E+161.E+170.0 0.2 0.4 0.6 0.8 1.0Depth (Microns)Concentration (cmPhosphorus and Fluorine Implantation Damage in SiliconImaged by Transmission Electron MicroscopyTaken by Dr Amy GandyA Bright field image taken down the (100) zone axisRegion 1Region 2F+ 185KeV 2.3x1015cm -2, P+ 100KeV 1x1015cm -2, 900°C, 30min in NitrogenRegion 1: extends from about 145nm below the surface and is 75nm wideRegion 2: extends from about 315nm below the surface and is 520nm wideDislocation Loops and Vacancy ClustersA Bright field , Off Bragg image of the Vacancy-Type defectsF+ 185KeV 2.3x1015cm -2, P+ 100KeV 1x1015cm -2, 900°C, 30min in Nitrogen200nmVacancy-ClustersDiscussion1.E+171.E+181.E+191.E+20Concentration (cm-3)P  F (As implanted) F (1000C,30s)Vacancy-Fluorine Clusters• Vacancy-Fluorine Clusters extend through out the F profile• The Phosphorus profile is entirely within the Vacan cy-fluorine Clusters Region• VF clusters resulted in an under saturation of inte rstitials and hence eliminated Phosphorus Diffusion1.E+160.0 0.2 0.4 0.6 0.8 1.0Depth (Microns)Concentration (cm-3)Conclusions• F+ implantation eliminated Phosphorus Diffusion !• F+ implantation is a simple and efficient technique to obtain shallow Phosphorus junctions in Silicon !

Defects induced by F+ implantation in SiGe observed by Transmission Electron Microscopy

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Defects induced by F+ implantation in SiGe observed by Transmission Electron Microscopy

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