1. Equipe Couches Nanométriques : Formation, Interfaces, Défauts
SAFIR : Un accélérateur Van de Graaff pour l’analyse de couches minces et ultra-minces
Equipe Couches Nanométriques : Formation, Interfaces, Défauts
SAFIR

4. General purpose IBA chambers UHV goniometer chamber
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
2.5 MV Van de Graaff
1H, 2H, 3He, 4He, C,N,O etc
Stable operation down to < 150keV
Beam energy resolution eV
Several mA in 2mm at target
MEIS
~10 permanent research/teaching staff
3 1/3 dedicated technical staff

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

6. Quelques sections efficaces
Pour un proton dans le silicium

7. The stopping power

8. The stopping power E-DE E Dx N atoms cm-3 Density r g cm-3
Units : eV cm2 atom-1
eV cm2 mg-1
eV nm-1

9. Rutherford Backscattering Spectrometry RBS

10. Détecteur particules
4He+
Bague isolante
Porte échantillon

12. E Nombre de coups x x x E K2E0 K1E0 Atome d’Aluminium Atome d’Or
Détecteur particules

13. RBS - principle E1 = k1 E E2 = k2 E 4He+ Energy E Detector Yield
Energy gives mass scale
Energy loss gives
depth scale
Intensity gives
concentration
Analytique !
Beam loses energy
4He+
Energy E
Trace of heavy element in a light substrate - eg Au in Si
Si Depth Si
surface
Detector
Au Depth
Yield Au
surface
E E2
Energy

14. Real RBS - Cu/Al2O3
Taken from work with R. Serna et al, Instituto de Optica, Madrid
Composite formed by alternate pulsed laser deposition of Cu and Al2O3.
Non-linear optical properties – amplification …
Structure supposed for RBS simulation
Surfaces layers, plus 7 times
90x1015 cm-2 Al2O (10nm)
45 Al2O3+30%Cu
plus
120x1015 cm-2 Al2O3
32 Al2O3+70%Cu
Artificially nanostructured Cu: Al2O3 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),

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

16. (conditions favorables)
RBS : Performances
(conditions favorables)
Sensibilité : at/cm2
Résolution en profondeur : 10 nm
Résolution en masse : 1 amu jusqu'à ~40 amu
Durée d'analyse : 5 minutes
Nécessite vide : <10-5 mbar

17. Nuclear Reactions

18. Nuclear Reactions Reaction Q (MeV) 12C(d,p0)13C 2.72 12C(d,p1)13C
Charged particle induced reactions : NRA Nuclear Reaction Analysis
Interaction is inelastic : internal energy needs to be included in the kinematics.
NRA is isotope-sensitive
(residual nucleus in ground state)
(residual nucleus in nth excited state, of energy En)
Reaction
Q (MeV)
12C(d,p0)13C
2.72
12C(d,p1)13C
-0.34
16O(d,p0)17O
1.92
16O(d,p1)17O
1.05

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

20. NRA Cross sections Strong variation with E0 Strong variation with q
Few reliable nuclear models
see SigmaCalc
See and R33 files distributed with SimNRA

21. NRA Thin Sample Principle
Cross section
2H+ 12
16O(d,p1)17O
qlab=150°
Absorber foil 10 8 ) -1
Detector
(mb sr
16O(d,p1)17O 6 s 4
16O(d,p0)17O 2
400
500
600
700
800
900
1000
1100
1200
Energy (keV)
Yield
12C(d,p0)13O
Incident beam energy
Energy (MeV)

22. Thin and Thick target NRA spectra
NRA Spectra from thin and thick Ta2O5 with small carbon contamination

23. NRA – isotopic profiling
Simultaneous profiling of 14N and 15N via 14N(d,a1)12C and 14N(d,a0)13C respectively.
Nitridation of a Ti6Al4V alloy : artificial hip, to improve biocompatibilty
Strong nitrogen exchange between the gas and the nitride is observed.
From I.C. Vickridge et al. Nucl. Instr. And Meth. B99 (1995) 454.

24. (conditions favorables)
NRA : Performances
(conditions favorables)
Sensibilité : at/cm2, 0.1%
Résolution en profondeur : 100 nm
Spécificité isotopique : Elements légers (H-Si)
Durée d'analyse : 5 minutes
Nécessite vide : <10-5 mbar

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

27. Narrow Resonance Profiling
18O(p,a)15N resonance at 151 keV.
16O2
then
18O2 Si
exchange
growth
SiO2
150
155
160
165
170
175
180
200
400
600
800

28. Growth of SiC nanocrystals at the SiO2/SiC interface
Silicon with thermally grown SiO2
1100°C annealing under CO
Quartz furnace
13C180
SiO2
The use of 13C18O allows us to :
observe the fate of C only from CO (13C) without being concerned with C contamination
quantitatively determine the fate of 18O from the CO (Si16O2 matrix)
SiC
SiO2
Moiré pattern Si Si
Epitaxial 3C - SiC
Cross sectional TEM image of a (100) Si/SiO2 system annealed in 100% CO at 1 Bar at 1100oC for 2hrs

29. Typical excitation curve
18O Excitation curves after 1100°C treatment for 90 min at 350mbar
The three regions in the 18O concentration profile reflect 3 processes
CO diffusion with exchange in volume Process I
Oxygen exchange at surface Process II
+ oxygen network diffusion
Oxygen incorporation at interface Process III
Volume 16O-18O exchange
Process I
Interface
reaction
CO interstitiel diffusion
SiC
Process II
SiO2 Si
An 18O study of the interaction between carbon monoxide and dry thermal SiO2 at 1100°C. Catherine Deville Cavellin, Isabelle Trimaille, Jean-Jacques Ganem, Marie D’Angelo, Ian Vickridge, Anita Pongracz and Gabor Battistig. Journal of Applied Physics (2009), 105,
Isotopic tracing study of the growth of silicon carbide nano-crystals at the SiO2/Si interface by CO annealing. A. Pongracz, Y. Hoshino, M. D’Angelo, C. Deville Cavellin, J.-J. Ganem, I. Trimaille, G. Battistig, K.V. Josepovits, I. Vickridge. Journal of Applied Physics (2009) 106,

30. Ratio of O to C incorporated in the interface region
90 min, 1100°C
We can now confidently conclude that
for each C atom incorporated in a SiC nano-crystal, an oxygen atom is incorprated in the SiO2/Si interfacial region.

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

32. Détecteur électrostatique toroïdal
permettant une analyse simultanée
en énergie (profil de composition)
en angle (structure)
des ions rétro-diffusés dans les premiers nm.
Si(100)
13A
SiO2
46A
La2Si2O7

33. MEIS : Typical example Medium Energy Ion Scattering
La2O3 (high k) deposited on Si, then oxidised : chemical reaction …
RBS relatively classical
200keV 4He+ dét. 15keV
Medium Energy Ion Scattering
(from M. Copel et al, IBM Almaden)

34. Comparaison MEIS – RBS RBS MEIS Résolution en profondeur 10 nm 0.3 nm
Profondeur explorable
1mm
20 nm
Sensibilité (at.cm-2)
1014
qqs 1012
MAIS : temps d’acquisition des spectres (RBS = 101 minutes, MEIS = 102 minutes
dégâts induits dans l’échantillon
physique sous-jacente +compliquée, moins bien maitrisée

36. One important topic we have not talked about : ion channelling
Amorphisation of Si by implantation of 29Si
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.
Matrice de 16 détecteurs pour ERDA (détection H)
Matrice de 16 détecteurs pour RBS
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