High Resolution Surface Mass Spectrometry by TOF-SIMS The challenge of chemical nanoanalysis Secondary Ion Mass Spec

1. High Resolution Surface Mass Spectrometry • by • TOF-SIMS • The challenge of chemical nanoanalysis • Secondary Ion Mass Spectrometry - SIMS • Analytical application of TOF-SIMS • Perspectives

3. Key questions in nanoanalysis • Identification (What?) • Localisation (Where?) • Quantification (How much?)

4. Nanotechnology Definition:In at least one dimension <100nm Example: Surface mapping Lateral resolution: 100 nm Information depth: 1 nm  Volume: 1x100x100 nm3 Amount of material: 0.1 attomole some 10.000 molecules

5. Chemical information ? • Proximity probes (AFM, SNOM, ..... ) • Electron emission based probes (XPS, AES, TEM, ….) • Surface mass spectrometry • Excitation by: • Electrons • Electrical fields Atom probe • Photons MALDI • Ions  Secondary Ion Mass Spectrometry (SIMS)

6. Ag catalyst

9. Secondary Ion Emission • M  Xiq • X1+, X2+, X3+, ...... Xi+, ............... • X1-, X2-, X3-, ....... Xi-, ............... • X1o, X2o, X3o, ....... Xio, ............... Transformation probability : P (M  Xiq)

10. Static SIMS  Negligible probability of bombarding a damaged area • Sputtering of only a negligible fraction of the uppermost monolayer • Reduction of the primary ion current (fluence) • Reduction of the secondary ion current • Resulting conditions/requirements • High transformation probabilities • High transmission mass spectrometer • High sensitivity secondary ion detection

13. Monolayer Sputtering • θ(t) = θ(0) . exp (- σ .ν . t) • θ(t) Fractional coverage at time t • σ Damage cross section • ν Primary ion flux density • θ(0) Fractional coverage at t = 0 • Lifetime t of one Monolayerθ(t) = θ(0) . 1/e • t = 1/( σ.ν)

14. Ag catalyst

15. Ag catalyst

16. ML sputtering Example: octanethiol on Au  = 1,34. 10-14 cm2 Static SIMS I = 0.6 pA A = 1.5610-4 cm2  = 13410-16 cm2

17. Mass analysers applied in Static SIMS • (Historical development) • Magnetic sector field •  • Quadrupole •  • (FT-ICR) •  • Time - of - Flight

18. TOF-SIMS

19. Main features of TOF-SIMS • Parallel mass detection • High (unlimited) mass range • High mass resolution > 10 000 • High mass accuracy (1-10 ppm) • High transmission for high masses and at high mass resolution • All elements and isotopes • Molecular species • High sensitivity (ppb, attomole) • High lateral (50 nm)and depth (1nm) resolution

20. Static SIMS Oxidized and contaminated molybdenum surface (1973)

22. Molecular Information by Static SIMS Example: Polystyrene I Intact Molecules (m < 10,000 u) (M+H)+, (M+Ag)+, (M+Na)+,(M-H)-, ... (“substrate cationization” only from (sub)monolayer coverages) II Characteristic Large Fragments loss of functional groups,repeat units,..…(according to “classical” fragmentation rules) III Small Organic Fragments end groups, fractions of repeat units, side chains,.…(sufficient for identification)

24. Static SIMS Phenylalanylglycine ML on Ag (1981)

25. Cyclosporine A

26. Conservation of charge signe • - Examples - • Al-oxide  Al+, O-, AlO+, AlO2-, ..... • Ag-sulfate  Ag+, SO4- , ........ • M on Ag  M+H+, M-H-, M+Ag+, ...... • Me-Cs  Me-, Cs+, .......

27. Transformation probabilities (M  Xiq) • -Examples - • Al P (Al Al+) = 0,007 • Al-oxide P (Al Al+) = 0,7 • Ag-sulfate P (-SO4 SO4-) = 0,3 • Me - Cs P (Cs Cs+) = 1,0 • Ag -Methionine P (MM+H+) = 0,005 • Ag - Bradikinin P (MM+H+) = 0,0001 (1.060 amu) • Ag -Mellitin P (MM+H+) = 0,000 000 5 (2.846 amu)

28. Damage cross sections σ - Examples - • System σ/10-14cm2 d/nm • Ni - O 0,25 0,5 • Ni - H 0,5 0,7 • Ni - H2 4,5 2,1 • Au - Thiole 1,3 1,1 • Ag - Methionine 4,5 2,3 • Ag - Bradikinin 20,0 4,9 (1.060 amu) • Ag - Melittin 45,0 7,4 (2.846 amu)

29. Sample materials, geometries, operation modes •  Sample materials • Metals, Semiconductors, Oxides, • Glasses, Ceramics, • Polymers, Additives, Biopolymers, Biomolecules • Biological tissues •  Sample geometries • Surfaces, Monolayers, Particles, Fibers, ..... •  Operation modes • Spectroscopy • Imaging (mapping) • Depth profiling • 3D-analysis

30. TOF - SIMS activities  250 laboratories are operating TOF-SIMS instruments worldwide  Bienniel International SIMS Conferences 2005: SIMS 15 (Manchester) 2007: SIMS 16 (Japan) (350 – 450 participants)  Bienniel European SIMS Conferences in Münster, Germany 2006 : SIMS Europe V (200 – 250 participants)

31. (Static) SIMS Optimisation •  Mass Spectrometry • Magnetic sector field  Quadrupole )  (FT-ICR) Time-of-Flight • Lateral resolution • Focused ion beams •  Depth resolution • Cluster bombardment • Low energy PI •  P(MX) • Oxidation, Cs deposition • Nobel metal substrates • Cluster bombardment

32. Mass resolution, accuracy

33. 16 % 84 % Lateral resolution Example: Photographic Crystals lateral distribution of Cl- on cubic silver halide crystals line profile x16%-84% = 50 nm (Sample provided by the University of Antwerp, Belgium (Prof. Gijbels))

34. B concentration / atoms/cm3 intensity depth / nm Deth resolution B monolayer in Si

35. Influence of the Substrate and the Surface Coverage Yield

36. Cluster bombardment O  Ar  Xe  SF5  CmHn  C60 Ga AunBin

37. Main features of TOF-SIMS • Parallel mass detection • High (unlimited) mass range • High mass resolution > 10 000 • High mass accuracy (1-10 ppm) • High transmission for high masses and at high mass resolution • All elements and isotopes • Molecular species • High sensitivity (ppb, attomole) • High lateral (50 nm)and depth (1nm) resolution

38. Trace Metal Detection / mass resolution mass resolution (FWHM): Ti:13119 Cr: 12813 Fe: 12009 Cu: 13849 coverage (atoms/cm2): Ti:6.1E10 Cr: 8.2E09 Fe: 3.1E09 Cu: 2.1E10 data taken from 003_r.dat

39. TOF-SIMS Detection Limits 1 Monolayer = 1.5E15 atoms/cm²)  the error is estimated to be within a factor of 2 to 3.

40. B concentration / atoms/cm3 intensity depth / nm depth / nm Depth profiling Reconstructed profile (Li, Na)

41. Material Science 2D Images and Cross Sections (Sample provided by Prof. Martin, RWTH Aachen, Germany)

42. Field of View: 284 x 284 µm2 Polymer (PP) Melt Stabiliser Polymer, Stabiliser, Antioxidant Antioxidant Surface Imaging Blooming Effect on Polymer

43. Particle Analysis / Uranium

44. Nanoextraction Laser-SNMS overlay TOF-SIMS overlay

45. 10 µm LB-multilayer system: Lipids: DPPC/DPPG (4:1),Protein: 0.4 mol% SP-C Protein Lipid Phase Separation Laser- SNMS FLM dye-labeled lipid 58: C3H8N 30: CH4N 10 µm TOF- SIMS + AFM topography 58: C3H8N 110: C5H8N3

46. Au2 imaging - Placenta cell complex

47. Mouse Brain Section Correlation Analysis: 3 Colour Overlay Field of View: 8 x 8 mm2 corpus callosum Fe caudateputammen sum of phospholipid ions canteriorcommissure sum ofcholesterol ions nucleustriangularissepti Example provided by Alain Brunelle,ICSN, CNRS, France

48. Rat Brain CrossSection Field of View: 18 x 18 mm2 255 Carboxylate 283 C18 Fatty acid 771 Phospholipid 892 Triclyceride to be published by A. Brunelle et. al. ICSN, CNRS, France

49. Salbutamol Field of View: 52.7 x 52.7 µm2 one pixel: 100 x 100 nm2 • only 100 shots applied • 20 integral counts Salbutamol Salbutamol (M+H)+ max counts: 20 total counts: 2.12 x 105  2 x 10-20 mole detected from a 100 nm spot

50. Applications in Life Sciences •  Fundamental research • Tissues, cells, membranes, biopolymers, lipids, ...... • Biomedicine, biology, biochemistry………. •  Diagnostics • Biochips, chromatographies, nanofluidics, marker, molecular pathology, …….. •  Drugs • Delivery systems (tablets, nanoparticles, polymers,..), localisation in cells and tissues (ADME), contamination, screening, ...... •  Biomaterials • Artificial membranes, substrates for cell growth and artificial tissues, protein- and cell-adhesion, biocompatibility, .....