PHI nanotof II TOF-SIMS. 1

Transcription

1 PHI nanotof II TOF-SIMS 1

2 25+ Years of TOF-SIMS at PHI Pulsed Cs Gun Direct Imaging TRIFT I LMIG PHI Purchased CE&A TOF-SIMS business New Cs gun 200 mm 300 mm TRIFT II Dual Source Column Larger Analyzer FOV DEM Detector Scanning TRIFT III 3D Imaging Au Emitter Stage Mapping TRIFT IV New LMIG Improved Au Performance with HR 2 Auto / Batch Data Processing Topo-Strip Data Processing TRIFT V nanotof Auto Startup Auto Shutdown New Bi Emitter 2016 Introduction of Parallel Imaging MS/MS nanotof II /SALI 7200 Pulsed Ar Excimer Laser VUV Laser In Emitter Stopped Development On 7200 New 5-axis Stage Dual-Beam Charge Comp 20 kv C 60 Auto / Unattended Analysis FIB-TOF GCIB Bi Emitter New LMIG Improved HR 2 Imaging New FIB New Cs Gun New GCIB PHI has a long history of developments to support new applications. 2

3 Highlights of the PHI nanotof II Unique features of the PHI nanotof II TOF-SIMS: Elemental, isotope and molecular fragment with high mass resolution and high sensitivity 16,000 m/δm mass resolution with ~ m/z 10,000 mass range > 1 part per million detection limits (Detection Limits ~10 9 at/cm 2 ) 70 nm Spatial Resolution with 2 nm surface sensitivity The large angular acceptance and depth-of-field characteristics of the TRIFT analyzer provide high sensitivity for chemical visualization of samples having rough surfaces. HR 2 chemical / molecular imaging enables the acquisition of data with simultaneous high lateral resolution and high mass resolution while also using a high analysis beam current, i.e. 1 na, so that the analysis times remain short, e.g. 10 minutes. The patented dual-beam charge neutralization system for ease-of-use in turn-key insulator analysis. The metastable rejection characteristic of the TRIFT analyzer generates data sets with high dynamic range and low spectral background. 3

4 TOF-SIMS Imaging Primary Ion Beam Total Ion Image Total Area Spectrum m/z Sample One imaging data file of a few minutes acquires a spectrum at every pixel of the image. The computer can reconstruct a total ion image or total area spectrum from this file. 4

5 TOF-SIMS Imaging Region 1 Spectrum Primary Ion Beam Chemical Map 1 Total Ion Image Total Area Spectrum m/z Region 2 Spectrum m/z Chemical Map 2 m/z Sample Spectra from selected areas of the total ion image or images from selected peaks of the total area spectrum can also be obtained for complete analysis after data acquisition. 5

6 Positive TOF-SIMS Spectrum of PET Intensity Fragments allow the molecular structure of the polymer repeat unit to be defined. 6

7 Intensity Positive TOF-SIMS Spectrum of PET The repeating peak patterns confirm the polymerization structure 7

8 Intensity Full Mass Spectrum at Every Depth Application: Interface Analysis 30 Si - Sample: 120 nm MoSi 2 /Si Objective: To measure determine the impurities at the interface. Approach: Interleaved Depth Profile 1 kev Cs + /15 kev Ga + MoSi - Raw-data-stream acquisition Extract spectrum at interface Depth (nm) 8

9 Intensity Full Mass Spectrum at Every Depth Intensity Application: Interface Analysis 30 Si - O Spectrum from interface (118 nm) SiO 2 SiC Si 3 MoSi - C 30 Si Si 2 MoSi Depth (nm)

10 Intensity Full Mass Spectrum at Every Depth Application: Interface Analysis 30 Si Reconstructed Depth Profile showing some of the interface impurities O Interleaved depth profiling ensures that the interface will not be missed C SiO 2 F MoSi Nanometers 10

11 PHI nanotof II TOF-SIMS With a Triple Ion Focusing Time-of-Flight (TRIFT) Mass Analyzer Energy Slit ESA 2 ESA 1 Superior imaging of rough & high topography surfaces Unique HR 2 capability high mass resolution with high spatial ESA 3 Cluster Guns Ar 2500+, C 60 q+ Sample Post-ESA Blanker FIB Gun Cesium Gun Imaging Aperture High Mass Blanker Gas Gun Ar +, O 2 + Ion Detector SE Detector LMIG Ga +, Au n q+, Bi n q+ resolution at high beam current Optional C 60 & GCIB sources for exceptional depth profiling & 3D imaging capabilities across a wide variety of materials Unique 3D chemical imaging by FIB-TOF tomography Superior Signal/Background organic spectra with metastable rejection due to TRIFT analyzer 11

12 Superior Imaging & Characterization of Rough, High Topography Surfaces 12

13 TRIFT Analyzer Design Philosophy Most Samples are Not Flat. If you can t image a feature, you can t determine the chemistry of that feature. 13

14 High Aspect Ratio Samples IC Bump Digitizer Trace Nozzle HD Head Many samples of complex shapes produce a distortion of the ion extraction fields causing difficulties for chemical imaging. Delayed extraction reduces these effects in other instruments, but limits the mass range and produces spectra with a non-linear mass scale. The TRIFT has both a large angular acceptance and a large depth-of-field to overcome these difficulties without using delayed extraction. 14

15 Large Angular Acceptance of TRIFT Analyzer Energy Slit Three spatial crossovers refocus divergent ions to generate a wide angular acceptance which is key for high topography samples. Metal interconnect Flexible Substrate Primary Ion Beam (40 ) Detector Total Ion Image Step Edge Immersion Lens Sample Triple Ion Focusing Time-of-Flight Mass Analyzer 15

16 Large Depth-of-Field for TRIFT Analyzer Energy Slit Higher energy ions travel a longer distance through the spectrometer and arrive at the detector at the same time as lower energy ions. The default position of the energy slit provides a 240 ev bandpass filter for excellent depth-of-field on high topography samples. Detector Poly Ethyl Methacrylate Immersion Lens Sample ~ 100 µm Acrylic Adhesive 16

17 Large Depth-of-Field Nonwoven Fiber Example Intensity Intensity Total Ion image, -SIMS, 200 µm field of view (FOV) q p o l m n k SIMS ROI spectrum from fiber o 297 -SIMS ROI spectrum from fiber j j m/z Exceptional imaging depth-of-field of > 150 µm (8 fibers each ~20-25 µm in diameter). Excellent spectral quality and high sensitivity is maintained at each fiber layer. 17

18 New & Unique HR 2 Analysis Mode: Simultaneous High m/δm and Small Δl at High Beam Current 18

19 Unbunched vs. Bunched (HR 2 ) Imaging Unbunched Imaging: Best Lateral Resolution, Δl ion pulses (Δt) typ. > 10 ns (Δl) < 70 nm high V low V pw t (rep. rate = 1/t) sample Bunched HR 2 Spectrometry: Best Mass Resolution, m/δm buncher (Δt) < 1 ns sample (Δl) < 500 nm HR 2 chemical / molecular imaging with the new PHI LMIG enables the acquisition of data with simultaneous high lateral resolution and high mass resolution while also using a high analysis beam current, i.e. 1 na, so that the analysis times remain short, e.g. 10 minutes. 19

20 Intensity HR 2 Imaging of Organic Micro-Droplets +SIMS; 25 µm FOV lateral resolution (Dl) < 400 nm 0.5 na beam current, 6 min. acq. C 4 H 9 10 µm 10 µm C 3 H 5 O Superior HR 2 imaging due to performance of new PHI LMIG. 20

21 Intensity Intensity Intensity HR 2 High Mass Resolution of Micro-Droplets C 2 H 3 O C 2 H 5 N +SIMS; sum over entire image area, 6 minutes data acquisition C 3 H 7 CH 3 N 2 m/δm = 9,292 (FWHM) C 2 F 5 m/δm = 12,100 (FWHM) C45 H 58 O 4 C 45 H 59 O 4 m/δm = 11,860 (FWHM)

22 Biological Sample: Arabidopsis Thaliana Use imaging mass spectrometry (TOF-SIMS) to: Investigate the similarities and differences in epicuticular wax composition of intact plant organ Interrogate the variance in composition among epicuticular cells Targeted organs and cells: In general, all major organs.. Stem Leaf (abaxial & adaxial) Flower Specialized cells Pavement (epidermal cell) Stomate (guard cell) Trichome ( hair or whisker ) Pollen (spore) 22

23 TOF-SIMS Images SEM Images Arabidopsis Thaliana: Specialized Cells spores stomata trichome dev.biologists.org botanicalgarden.ubc.ca planttrichome.org 10 mm 10 mm 100 mm High spatial resolution total ion imaging of specialty cells 23

24 Intensity Intensity Intensity Arabidopsis Thaliana: Surface Lipid Composition of Cells -SIMS from ROI-1: inside the stomate Stomates have sizes of approximately 1 x 7 µm. ROI-1 ROI-3 ROI-2 Total Ion Image (-SIMS) SIMS from ROI-3: pavement cells SIMS from ROI-2: guard cells Tricontanol Nonacosanoic Acid 1-Tricontanol Tricontanol Nonacosanoic Acid Low noise, high signal-to-background for stomate cell due to superior TRIFT analyzer with metastable ion rejection. 24

25 Intensity Intensity Arabidopsis Thaliana: Surface Lipid Composition of Cells Requires > 200 µm depth-offield for chemical imaging. ROI-2 ROI-1 +SIMS from ROI-1 of the trichome Nonacosanoic Acid 1-Tricontanol SIMS from ROI-2 of the underlying pavement cells Total Ion Image (+SIMS) Nonacosanoic Acid High signal-to-background for trichome with high depth of field due to superior TRIFT analyzer. 25

26 Intensity Optional C 60+ Molecular Lipid Imaging of Mouse Brain m/z E+5 1.0E+5 m/z 772 m/z m/z 798 m/z E+4 6.0E+4 4.0E m/z 788 m/z 184 (phospholipid head group) 2.0E m/z 369 (cholesterol) Mass [m/z] 26

27 Dual Beam Charge Neutralization For Insulators like Polymers and Life Science Samples An electrostatic charge on the insulating sample surface may repel electrons from a low energy flood gun and prevent effective charge neutralization. Focused Primary Ion Beam PHI s patented* dual beam charge neutralization method uses a low energy ion beam to eliminate electrostatic charges on the sample surface and a low energy electron beam to neutralize the charge created by the primary ion beam. Focused Primary Ion Beam Negative Static Charge Insulating Sample Low Energy Electron Source Low Energy Positive Ion Source Sample Platen Insulating Sample Low Energy Electron Source Collection of high quality data quickly without any tuning of the neutralization settings, the spectrometer, or recalibration of the mass spectrum. Easy single parameter insulator analysis is accomplished with only adjustment of the sample bias since the spectrometer is grounded. * US Patent 5,990,476, JP Patent P , EP Patent B1 27

28 Optional Ion Guns for Depth Profiling 28

29 O 2 + Ion Gun Sputter Depth Profiling Excellent Comparison between TOF-SIMS vs D-SIMS Layer (Depth Resolution) D-SIMS TOF-SIMS 29

30 Depth Resolution Test Sample: Optional Cs + Gun Chromium (60 nm) Nickel (60 nm) Silicon (substrate) 30

31 Dual-Beam Interleaved Depth Profiling with Cs + Gun Intensity Cr/Ni Multi-layer Analysis Ni Negative SIMS 1 kev Cs + ; 250 x 250 µm 2 15 kev Ga + ; 25 x 25 µm 2 Oxygen enhancement of Ni at interfaces Cr Depth (nm) 31

32 Intensity Dual-Beam Interleaved Depth Profiling with Cs + Gun Cr/Ni Multi-layer Analysis CsM + improves quantification Positive SIMS (CsM + ) CsCr + 1 kev Cs + ; 250 x 250 µm 2 15 kev Ga + ; 25 x 25 µm 2 More uniform Relative Sensitivity Factors CsNi Depth (nm) 32

33 Optional Gas Cluster Ion Beam (GCIB) Depth Profiling ~ 225 nm PS 9 delta layers of P2VP Si substrate PS: polystyrene P2VP: poly(2-vinylpyridine) 33

34 Intensity GCIB Depth Profile +SIMS; 60 kev Bi 3 ++ analysis; 5 kev GCIB (Ar 2,500+ ) sputtering Total Ion Si The depth profile of the P2VP delta layers are clearly observed by the C 7 H 8 N + monomer signal in the PS matrix. The polymer signals are stable throughout the multilayer film. There is some signal fluctuation at the Si substrate interface as a result of the presence of the native oxide. NOTE: The depth scale is estimated based on the analysis conditions and against the previous analysis. C 7 H 7 C 7 H 8 N C 3 H 9 Si The Si arises from both the substrate and the silicone contamination (predominantly at the surface). It is not observed to increase as a function of depth until the substrate is reached Depth (nm) 34

35 Intensity GCIB Depth Profile of PS/P2VP +SIMS; 60 kev Bi 3 ++ analysis; 5 kev GCIB (Ar 2,500+ ) sputtering 9 bi-layers (18 total layers). The P2VP and PS profiles are shown overlayed on a linear intensity scale. A total of 18 layers (9 bi-layers) were measured before reaching the Si substrate. NOTE: The depth scale is estimated based on the analysis conditions and against the previous analysis. C 7 H 7 C 7 H 8 N (x1.8) Depth (nm) 35

36 3D Iso-Surface Imaging of PS/P2PV +SIMS; 60 kev Bi 3 ++ analysis; 5 kev GCIB (Ar 2,500+ ) sputtering C 7 H 7+ (PS, 91m/z); C 7 H 8 N + (P2VP, 106m/z); Si + (28m/z) surface Si from silicone (i.e. PDMS) surface Si from substrate 36

37 Intensity Optional C 60+ vs. Ar + Profiling of Sol-Gel +SIMS; 5 kev Ar + sputtering Total Ion Al Mg Si C Cu Sputter Crater The Si/Al stoichiometry appears to change as a function of depth. The C signal also varies as a function of depth. There is substantial Cu at the surface and again at the solgel/al interface. The sol-gel/al interface appears thick and disordered; however, the nonuniformity may be a result of roughness induced by the sputter beam. The depth scale is estimated; the sputtered depth was not measured by profilometry Depth (nm) 37

38 Intensity Optional C 60+ vs. Ar + Profiling of Sol-Gel +SIMS; 40 kev C sputtering Total Ion Al Mg Si C Cu Sputter Crater The interface transients are essentially nonexistent which improves the capability for quantitative data analysis. The ion signals are relatively constant indicating a uniform Si/Al stoichiometry. There is no C build-up from the C 60 sputter beam. The sol-gel/al interface appears more sharp indicating either a more uniform sputter crater produced by the C 60 beam or a more homogeneous film. The depth scale is estimated; the sputtered depth was not measured by profilometry Depth (nm) 38

39 Optional C 60+ vs. Ar + Profiling of Sol-Gel Si / Al (x10 4 ) The C 60 sputtering produces a better profile result. The stable Si/Al stoichiometry is likely the result of (a) uniform sputter rates of the various matrix elements, and (b) a flat bottom sputter crater. C 60+ /C profile Bi 3 ++ /Ar + profile Depth (nm) 39

40 Preferred Sputter Gun Options: Material Dependent Ion Gun Ar + / O 2 + Cs + C 60 +n Ar n+ Cluster Sample Type Metals Preferred for +SIMS More uniform ion formation yield > 20 kv minimizes carbide formation Very slow sputter rates, material dependent Ceramics Glasses Oxides Differential sputtering and chemical changes Preferred for negative SIMS like Cl -, F - and MetalO x - Excellent for glasses, metalloid alloys and many oxides Very slow sputter rates, with damage of TiO 2, HfO 2 and some other oxides Organics Polymers Severe chemical damage Severe chemical damage Excellent for chain scission polymers Excellent for chain scission and crosslinking polymers Mixed Organics and metals/oxides Severe damage of organic components Severe damage of organic components Excellent sputter rates of all components Very slow sputter rates of inorganic components Semiconductors Preferred for +SIMS Preferred for -SIMS Not preferred Not applicable 40

41 C 60+ and Gas Cluster + Ion Gun Comparisons Ion Gun Advantages Disadvantages 20 kv C 60 q+ Bunched m/δm > 5,000 FWHM Small spot size (Δl < 2 µm) Consistent sputtering of inorganic specimens Best sputter gun for mixed composition materials Ideal for single-gun analysis of chain scission polymers and biological specimens 20 kv Ar n + (n = 400 to 4,000) Efficient sputtering for organic and biological specimens Very high organic sputter rates Not ideal for sputtering of crosslinking polymers Slow organic sputter rates compared to GCIB Large spot size (Δl > 25 µm) Very low inorganic sputter rates High differential sputter rates between organic and inorganic phases 41

42 Optional FIB for FIB-TOF Tomography 42

43 3D Imaging by FIB-TOF Tomography Tomography sample preparation FIB sectioning TOF-SIMS ion & electron imaging image processing Sample stage is not moved between sectioning and ion/electron imaging. FIB Imaging Plane z y x LMIG 43

44 3D FIB-TOF Imaging of Solid Oxide Fuel Cell: SOFC 44

45 Full Chemical Characterization of a SOFC Ion-Induced SE Image PrSrCoO x Gd-doped CeO x Sc-stabilized ZrO x Intensity All 14 elements present in the matrix (not including 69 Ga/ 71 Ga) are detected. With the TRIFT mass analyzer, the full mass spectrum is collected at every image pixel. There is no need to use delayed extraction in order to obtain high collection efficiency or uniform signal for imaging. 45

46 Intensity Identification of Matrix Components Isotopic abundances are used to confirm peak assignments. ôô Sr õì Zr Y 84 Sr ôò Sr ôó Sr õí Zr õî Zr õð Zr õò Zr Example showing isotopic identification of Sr, Y and Zr. There is high confidence for the identification of Sr, Y and Zr based on the expected isotopic distributions. There is also high confidence for the identification of Li, B, Na, Mg, Al, Si, K, Sc, Ni, Co, Ce and Pr. Minor isotopes of Gd were used for imaging due to interferences. 46

47 3D FIB-TOF Imaging of a SOFC Imaged volume is 50 mm x 50 mm x 10 mm. direction of FIB sectioning Sr +, Ce +, Zr + and K + iso-surface overlay. Note K + decorating the void surfaces. 47

48 Optional MS/MS for High Mass, Unambiguous Peak Identification 48

49 Why is MS/MS Required in TOF-SIMS? Practical mass resolution of polymers/tissue ~ 10,000 m/δm. Mass accuracy is limited to ~ ppm. Given the practical mass resolution and mass accuracy limits, it is not possible to unambiguously determine the chemical formula of an ion above ~ m/z 200. Additionally, there is no way to resolve overlapping peaks and isobaric (same nominal mass) molecular ions at high mass. 49

50 TOF-SIMS Parallel Imaging MS/MS True Parallel and Synchronous MS 1 and MS 2 Data Acquisition Pulse counting TOF provides greatest speed and sensitivity Full MS 1 and MS 2 mass spectra collected at every image pixel Narrow mass precursor selection window (m/z 1 at m/z 500) for user selection of 12 C vs 13 C composition Parallel Imaging MS/MS available for imaging, mosaic mapping, and depth profiling High conversion efficiency of precursors with high energy collision induced dissociation (CID) 50

51 Analysis of PET Surface Features PET (poly (ethylene terephthalate)) film heated to o C for 2 hours. Surface features appear as surface crystals in optical microscope and secondary electron and secondary ion images. What is the chemical composition of these features which have a common peak at +m/z 577? Analysis conditions 40 mm FOV; 256 x 256 pixels 6 na Bi 3+ ; unbunched 4.82 x10 12 Bi 3+ /cm 2 ; 13 min 51

52 Intensity Intensity Precursor Ion Selection of +m/z 577 MS 1 Spectra Without and With 100% Precursor Ion Selection MS 1 Spectrum with Precursor Selector OFF MS 1 Spectrum with Precursor Selector ON Precursor = m/z

53 Intensity MS 2 Compositional Peak Assignments MS 2 Spectra are Generated with > 25% CID Precursor Ion Fragmentation The +m/z 577 peak of heat-treated PET is confirmed to be ethylene terephthalate trimer. The MS 2 results are accomplished at < 5 mda RMS mass deviation, and 3.8 ppm mass accuracy at the precursor. 53

54 High Lateral Resolution Parallel Imaging MS/MS 40 mm FOV; 256 x 256 pixels; 6 na Bi 3+ ; PIDD = 4.82x10 12 Bi 3+ /cm 2 ; 13 minutes MS 1 10 mm 10 mm 10 mm Total Ion (+SIMS) C 8 H 5 O 3+ (m/z 149) C 7 H 4 O + (m/z 104) MS 2 10 mm 10 mm 10 mm Total Ion (+SIMS) C 8 H 5 O 3+ (m/z 149) C 7 H 4 O + (m/z 104) The +m/z 577 peak arises almost exclusively from the surface crystals, as emphasized in the parallel MS 1 and MS 2 images; the MS 2 images are free of chemical noise. 54

55 Measured Lateral Resolution at +m/z mm FOV; 256 x 256 pixels; 6 na Bi 3+ ; 13 minutes MS 1 Measured Lateral Resolution Dl 80/20 = 172 nm MS 2 Measured Lateral Resolution Dl 80/20 = 148 nm Unbunched (MS 1 spectra) LIMG with < 100 nm beam size 55

56 Total Counts (x10 5 ) Tandem MS of Erucamide -m/z MS 2 (m/z scale) 42 CON [M - H] [M - CH 4 ] - C [M - H O] - 5 H 8 ON - C H 7 ON C H 4 ON [M - NH 3 ]- C 2 H 4 ON CH 2 -CH 2 -CH 2 -CH 2 -CH 2 -CH 2 -CH 2 -CH 2 -CH 2 -CH 2 -CH 2 -CH 2 -CH 2 -CH 2 -CH 2 -CH x The MS 2 results are accomplished at < 5 mda RMS mass deviation. CID of M-H precursor shows complete structure with possible C=C bond position. 56

57 PHI nanotof II TOF-SIMS Comprehensive TOF-SIMS Options for Real World Samples 57