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SAFIR : Un accélérateur Van de Graaff pour lanalyse de couches minces et ultra-minces Equipe Couches Nanométriques : Formation, Interfaces, Défauts SAFI.

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Presentation on theme: "SAFIR : Un accélérateur Van de Graaff pour lanalyse de couches minces et ultra-minces Equipe Couches Nanométriques : Formation, Interfaces, Défauts SAFI."— Presentation transcript:

1 SAFIR : Un accélérateur Van de Graaff pour lanalyse de couches minces et ultra-minces Equipe Couches Nanométriques : Formation, Interfaces, Défauts SAFI R



4 2.5 MV Van de Graaff 1 H, 2 H, 3 He, 4 He, C,N,O etc Stable operation down to < 150keV Beam energy resolution 50-100eV Several A in 2mm at target The SAFIR Laboratory General purpose IBA chambers 10 -7 mbar RBS, NRA, NRP, ERDA Fast opening and pumping Large sample holder Goniometer chamber for channeling UHV goniometer chamber 10 -11 mbar LEED/Auger Channeling/Blocking Evaoprators Sample heating and cooling Rare gas handling MEIS ~10 permanent research/teaching staff 3 1/3 dedicated technical staff

5 Energy loss PIXE Elastic Scattering Nuclear Reactions Narrow resonance profiling Energy range 0.1-10 MeV Projectiles protons, deuterons, alphas, 3 He Ion Beam Analysis (IBA)

6 Quelques sections efficaces Pour un proton dans le silicium

7 The stopping power

8 x E E- E Units : eV cm 2 atom -1 eV cm 2 g -1 eV nm -1 N atoms cm -3 Density g cm -3

9 Rutherford Backscattering Spectrometry RBS

10 Bague isolante 4He+ Détecteur particules Porte échantillon


12 K1E0K1E0 E E K2E0K2E0 Détecteur particules x x x Atome dOr Atome dAluminium Nombre de coups E

13 RBS - principle 4 He + Energy E Trace of heavy element in a light substrate - eg Au in Si 0 E 1 E 2 Yield Detector E 1 = k 1 E E 2 = k 2 E Energy gives mass scale Au surface Si surface Au Depth Si Depth Beam loses energy Energy Energy loss gives depth scale Intensity gives concentration Analytique !

14 Taken from work with R. Serna et al, Instituto de Optica, Madrid Structure supposed for RBS simulation Composite formed by alternate pulsed laser deposition of Cu and Al 2 O 3. Non-linear optical properties – amplification … Real RBS - Cu/Al 2 O 3 Surfaces layers, plus 7 times 90x10 15 cm -2 Al 2 O 3 (10nm) 45Al 2 O 3 +30%Cu plus 120x10 15 cm -2 Al 2 O 3 32Al 2 O 3 +70%Cu Artificially nanostructured Cu: Al 2 O 3 films produced by pulsed laser ablation. R. Serna, C.N. Afonso, C. Ricolleau, Y. Wang, Y. Zheng, M. Gandais, I. Vickridge. Appl. Phys. A. 71 (2000), 583-586.

15 From P. Skeldon et al, Corrosion Centre, University of Manchester RBS – Anodisation of Au/Al alloy Au/Al alloy (4.5%Au) Anodic oxide H. Habazaki, K. Shimizu, P. Skeldon, G.E. Thompson, G.C. Wood, and X. Zhou, J. Phys. D: Appl. Phys. 30, 1833 (1997).

16 RBS : Performances Sensibilité : 10 14 at/cm 2 Résolution en profondeur :10 nm Résolution en masse :1 amu jusqu'à ~40 amu Durée d'analyse :5 minutes Nécessite vide :<10 -5 mbar (conditions favorables)

17 Nuclear Reactions

18 Charged particle induced reactions : NRA Nuclear Reaction Analysis Interaction is inelastic : internal energy needs to be included in the kinematics. NRA is isotope-sensitive ReactionQ (MeV) 12 C(d,p 0 ) 13 C2.72 12C (d,p 1 ) 13 C-0.34 16 O(d,p 0 ) 17 O1.92 16 O(d,p 1 ) 17 O1.05 (residual nucleus in ground state) (residual nucleus in n th excited state, of energy E n )

19 NRA Kinematics lab =150°, E d =1.4 MeV,mylar foil 12 m stops 0.9 MeV 2 H 2.8 MeV 4 He E.g. (d,p) reactions on light nuclei

20 NRA Cross sections See, and R33 files distributed with SimNRA Strong variation with E 0 Strong variation with Few reliable nuclear models see SigmaCalcSigmaCalc

21 NRA Thin Sample Principle 2H+2H+ Energy (MeV) Detector Absorber foil 16 O(d,p 0 ) 17 O 16 O(d,p 1 ) 17 O 12 C(d,p 0 ) 13 O 400500600700800900100011001200 0 2 4 6 8 10 12 (mb sr ) Energy (keV) 16 O(d,p 1 ) 17 O lab =150° Yield Cross section Incident beam energy

22 Thin and Thick target NRA spectra NRA Spectra from thin and thick Ta 2 O 5 with small carbon contamination

23 NRA – isotopic profiling Simultaneous profiling of 14 N and 15 N via 14 N(d, 1 ) 12 C and 14 N(d, 0 ) 13 C respectively. From I.C. Vickridge et al. Nucl. Instr. And Meth. B99 (1995) 454. Strong nitrogen exchange between the gas and the nitride is observed. Nitridation of a Ti6Al4V alloy : artificial hip, to improve biocompatibilty

24 NRA : Performances Sensibilité : 10 14 at/cm 2, 0.1% Résolution en profondeur :100 nm Spécificité isotopique :Elements légers (H-Si) Durée d'analyse :5 minutes Nécessite vide :<10 -5 mbar (conditions favorables)

25 High depth resolution IBA 2MeV 4 He in Ni x=16nm 500 keV 4 He in Si x=29nm e.g. RBS, E det = 10keV : Remove the detector Nuclear Resonance Profiling NRP Reduce E det Electrostatic or Magnetic spectrometers MEIS Reduce x?


27 Narrow Resonance Profiling 18 O(p, ) 15 N resonance at 151 keV. 16 O 2 then 18 O 2 Si exchange growth SiO 2

28 Growth of SiC nanocrystals at the SiO 2 /SiC interface Silicon with thermally grown SiO 2 1100°C annealing under CO Quartz furnace SiO2 Si 13 C 18 0 SiC SiO 2 SiEpitaxial 3C - SiC Cross sectional TEM image of a (100) Si/SiO 2 system annealed in 100% CO at 1 Bar at 1100 o C for 2hrs Moiré pattern The use of 13 C 18 O allows us to : – observe the fate of C only from CO ( 13 C) without being concerned with C contamination – quantitatively determine the fate of 18 O from the CO (Si 16 O 2 matrix)

29 Typical excitation curve 18 O Excitation curves after 1100°C treatment for 90 min at 350mbar The three regions in the 18 O concentration profile reflect 3 processes CO diffusion with exchange in volumeProcess I Oxygen exchange at surfaceProcess II + oxygen network diffusion Oxygen incorporation at interfaceProcess III Si SiC SiO 2 Volume 16 O- 18 O exchange CO interstitiel diffusion Interface reaction Process I Process II An 18 O study of the interaction between carbon monoxide and dry thermal SiO 2 at 1100°C. Catherine Deville Cavellin, Isabelle Trimaille, Jean-Jacques Ganem, Marie DAngelo, Ian Vickridge, Anita Pongracz and Gabor Battistig. Journal of Applied Physics (2009), 105, 033501. Isotopic tracing study of the growth of silicon carbide nano-crystals at the SiO 2 /Si interface by CO annealing. A. Pongracz, Y. Hoshino, M. DAngelo, C. Deville Cavellin, J.-J. Ganem, I. Trimaille, G. Battistig, K.V. Josepovits, I. Vickridge. Journal of Applied Physics (2009) 106, 024302.

30 Ratio of O to C incorporated in the interface region We can now confidently conclude that for each C atom incorporated in a SiC nano-crystal, an oxygen atom is incorprated in the SiO 2 /Si interfacial region. 90 min, 1100°C

31 Electrostatic detector Medium Energy Ion Scattering Semiconductor detector p-type silicon undepleted region depleted region deposited energy

32 46A La 2 Si 2 O 7 13A SiO 2 Si(100) Détecteur électrostatique toroïdal permettant une analyse simultanée en énergie (profil de composition) en angle (structure) des ions rétro-diffusés dans les premiers nm.

33 La 2 O 3 (high k) deposited on Si, then oxidised : chemical reaction … RBS relatively classical 200keV 4 He + dét. 15keV M edium E nergy I on S cattering (from M. Copel et al, IBM Almaden) MEIS : Typical example

34 RBSMEIS Résolution en profondeur10 nm0.3 nm Profondeur explorable 1 m 20 nm Sensibilité ( -2 )10 14 qqs 10 12 Comparaison MEIS – RBS MAIS : temps dacquisition des spectres (RBS = 10 1 minutes, MEIS = 10 2 minutes dégâts induits dans léchantillon physique sous-jacente +compliquée, moins bien maitrisée


36 One important topic we have not talked about : ion channelling Amorphisation of Si by implantation of 29 Si But, damage …

37 Augmenter l'angle solide des détecteurs de particules, sans perdre en résolution en énergie Réduire dose nécessaire pour obtenir spectres utiles (Aussi polymères, hydrogène …)

38 Design and build large area segmented particle detectors. 16 spectra collected simultaneously, at various angles 20 to 40 times greater solid angle for detection Spectroscopic tests underway in Rossendorf. Installation at INSP at end 2010 probably… Détecteurs pour tests Matrice de 16 détecteurs pour RBS Matrice de 16 détecteurs pour ERDA (détection H)

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