1. Ion Beam Analysis Part 1 Henri I. Boudinov
Instituto de Física, Universidade Federal do Rio Grande do Sul
Porto Alegre, RS, Brazil
26_10_2009 NanoSYD, MCI, SDU, Sønderborg , Denmark

2. Outline The Porto Alegre Ion Beam Centre
Interaction of ions with matter
Stopping power
Rutherford Backskattering Spectrometry (RBS)
Channeling
Compositional and defect depth profiles
Proton Induced X-ray emission (PIXE)
Nuclear Reaction Analysis (NRA)
Microbeam analysis

3. Porto Alegre Ion Beam Centre established in 1981
Controllable Materials Modification
Facilities
0.2-3MV Tandetron
30-500kV Single Ended Implanter
10-250kV Medium Current Implanter
Implantation 10keV ~15MeV (up to 1mA)
Sample size up to 10cmx10cm
Hot (800oC) or cold (~LN)
Applications
Ion Beam Synthesis
Buried and surface oxides and silicides
Nanocristals
Ion Implantation
Defect Engineering
Proton beam lithography
potentially 1m resolution to 10m depths

4. Porto Alegre Ion Beam Centre
Advanced Materials Analysis
Facilities
3MV Tandem
Techniques include RBS, MEIS, ERDA, PIXE, NRA
Channelling Spectroscopy for damage analysis
Fully automated collection and analysis
Micro-beam with full scanning
External Beam for vacuum sensitive samples
Applications
Thin Film Depth Profiling
Compositional Analysis
Disorder Profiling of Crystals
3-D elemental composition and mapping

5. Ion Beam for: Ion Beam Modification of Materials Ion Beam Analyses
Material Science
Solid State Physics
Atomic and Molecular Physics
Ion Beam Modification of Materials
Ion Beam Analyses
Basic Physics

6. Penetration of the Radiations in Solids
Charged Particles
Electrons: e-, e+, b-, b+ 10m
Ions: p+, He++ (a), etc m
Uncharged Particles
X-rays and g-rays 10cm
neutrons 10cm

12. Ion Implanter

13. 3MV Tandetron accelerator

15. Penetration of charged particles through matter
E. Rutherford, 1911
N.Bohr, , 1948
E. Fermi, 1924-
H.A. Bethe, 1930-
F. Bloch, 1933-
L. Landau, 1944-
....
Experimental ingredients
Ions : Z1=-1,1,2,...~100, electrons, muons, clusters,...
energies ~1eV – 1011 eV
Target : Z2 = 1,2,.. ~100, solids, gases, liquids, plasma,...

16. Bohr, Bethe,...

17. dE/dx = N.S Stopping Power dE/dx – energy loss [eV/nm]
N – atomic density [nm-3]
S – stopping power [eV.nm2]

18. dE/dx : two types

19. Low energies vion << ve : the electrons shield (passive)
Elastic Collisions
The ion lose energy to move the target atoms
Nuclear Stopping Power
Classic

20. High energies
vion ~ ve : active electrons (ionization/excitation, plasmons,...)
Inelastic Collisions
The ion lose energy to the electrons of the target
Electronic Stopping Power
Quantum

21. Electronic Energy loss (high energies)
Classical theory
dE/dx ~Z12 ln (|Z1|)
for Z1/v >> 1
Quantum theory
dE/dx ~Z12
First-order : for Z1/v <<1

22. Coupled-Channel Calculations
Results from
Coupled-Channel Calculations
proton (b=1) on H(1s)

23. Coupled-Channel Calculations
Results from
Coupled-Channel Calculations
anti-proton (b=1) on H(1s)

25. Transition from electronic to nuclear stopping power

26. Penetration of Ions in Silicon
Energy Loss

28. The Stopping and Range of Ions in Matter
Software SRIM

29. Materials Radiation Analysis Concept

30. AES (electron in and out) RBS, MEIS, LEIS, ISS (ion in and out)
XRF (X-ray, in and out)
XPS (X-ray in, electron out)
SEM/EDS (electron in, X-ray out)
SIMS and ERDA(ion in, target out)
PIXE (ion in, X-Ray out)
PIGE, NRA, ...
Auger electron spectroscopy (AES)
Secondary ion mass spectroscopy (SIMS)
X-ray fluorescence spectroscopy (XRF)
Electron microprobe analysis (EMA)

31. Ion Beam Analysis (IBA)
RBS
Energy of recoiling protons give element composition and elemental depth profiles
STIM
Measure the energy loss of transmitted ions to map density variations
Sample
1 – 3 MeV proton beam
PIGE
Nuclear reactions give characteristic gamma rays from light nuclei (e.g. Li, B, F)
PIXE
Characteristic X-ray emission
Simultaneous part-per-million detection of trace elements from Na to U

33. Rutherford BackScattering
Energy of ions recoiling from nuclear collisions depends on mass and depth
Measure light elements (C,N,O) and thickness or depth profiles
MDL around 0.1%, but can be used to help quantify PIXE
Incident Ion
Sample
To detector C O Na Cl
RBS
Spectrum of 2mm diameter marine aerosol particle showing sodium and chlorine and carbon and oxygen from the plastic support film

34. Backscattering Spectrometry
Yield
Concentration
Energy
Element (K)
Depth (dE/dx)

36. K = E1 /E0 E1 E0

37. E1 = K E - dE/dx(out) x / cos q2
E = E0 – dE/dx(in) x / cos q1
E1 = K E - dE/dx(out) x / cos q2
K E0 - E1
x =
K dE/dx(in) / cos q1 + dE/dx(out) / cos q2

39. RBS profiling

40. Fluctuations 1 Physics 2 3 Dx number of collisions impact parameter
charge state
... 1
Physics 2 3
roughness
detector parameters
beam spot
....
Forte dependencia nas condições iniciais. Part. 1 sofre mais colisões que a part. 3. Mas isto não significa que a primeira perderá mais energia.
Uma única colisão violenta (tipo head on) pode afetar muito mais a trajetória que milhares de colisões tipo soft. Dx

41. Energy straggling
Beam spot
Multiple scattering
Detector aceptance

43. monocrystal

46. Thin Film Analysis Structural information (near surface region)
Increased sensitivity to light impurities

47. Surface Peak
A aplicação de feixes de íons para estudar a estrutura de superfícies depende 1) medida acurada do pico de superfície 2) capacidade de prever (simular) esta estrutura para uma dada superfície.
RBS
MEIS

48. MEIS Si peaks: SIMOX better than Si As+ 20keV, 5E14 cm-2 + annealing:
RTA better than FA
As+ 20keV, 5E14 cm-2 + annealing:
RTA 1000C/10s or FA 950C/15min

49. Rutherford backscattering spectrometry (RBS)
Nondestructive and multielemental analysis technique
Elemental composition (stoichiometry) without a standard (1-5% accuracy).
Elemental depth profiles with a depth resolution of nanometers and a maximum depth of microns.
Surface impurities and impurity distribution in depth (sensitivity up to sub-ppm range).
Elemental areal density and thus thickness (or density) of thin films if the film density (or thickness) is known.
Diffusion depth profiles between interfaces up to a few microns below the surface.
Channeling-RBS is used to determine lattice location of impurities and defect distribution depth profile in single crystalline samples

50. Elastic Recoil Detection Analysis

51. Proton Induced X-ray Emission
Analogous to EDS using MeV protons
No primary bremsstrahlung, so low detection limits (1-10ppm)
Can be made quantitative Fe Cu Zn K Ca
PIXE

52. PIXE
Target
(Ca)
Beam
Detector
Counts
Electronics
K K
Energy

54. Applications Microelectronics Environmental sciences Food processing
Biological tissues
Biotechnology
Archaeology - Art
Earth Sciences

55. Proton Induced Gamma Ray Emission
MeV protons can tunnel through the Coulomb barrier of light nuclei to induce gamma emitting nuclear reactions
Gamma energy is characteristic of specific isotopes
Detection limits ~ 0.1 %
Useful for specific problems (e.g. F19, B10/B11) ^0 ^1 ^2 ^3
100
300
500
700
900
1100
1300
1500
1700
f:\pc_users\jpn\971118\490001g4._ : Tourmaline std: GRR573 F
B10 Al Li Na
Tourmaline standard GRR573
PIGE

56. Nuclear Reaction Analysis (NRA)
p + 18O 15N + 4He

58. Nuclear Microscopy
All types of data can be collected simultaneously

59. Scanning Transmission Ion Microscopy
Energy loss of transmitted ions depends on thickness and density.
Use energy loss mapping to image the structure of thin samples (up to 30m).
(No chemical information)
STIM
STIM image of the leg and claw of a wasp showing internal detail