CEA-Leti / DTSI / SCMC MINATEC Campus, 17 rue des … · CEA-Leti / DTSI / SCMC MINATEC Campus, 17 rue des Martyrs 38054 GRENOBLE Cedex 9 ... Technology ©CEA. All rightsreserved

Some of the possibilities offered by x-ray tomography,

electron tomography, ion beam tomography and

atom probe tomography

P. BleuetCEA-Leti / DTSI / SCMC

MINATEC Campus, 17 rue des Martyrs

38054 GRENOBLE Cedex 9

© CEA. All rights reserved

Noesis workshop @ Lafarge 13/10/2011 | 2

Technological ResearchApplication to KETs

Fundamental ResearchDevelopment of new

caracterisation technics

IndustryService to entreprise

Nano Characterisation platformScience

Industry

Technology



Microelectronics & 3D

� Characterisation is essentially 2D so far� Surface analyses within the first nanometers (TEM,ion, XPS, XRR)

� Micro & nanoelectronics is now 3D� MEMS, NEMS

� 3D integration

� 3D transistors

� 3D techniques and tomographic techniques are crucial !





Microtomography & resolution

� CCD (or CMOS)-based detection� Fast, low

� Dynamic range, cooling

� Readout time < 0.1s

� Matrix & pixel size

� Optics� X/visible conversion

� Virtual pixel size

� Typically 0.28 to 20 microns

Beam

Sample

Scintillator screen Lenses and mirror

CCD

Lack of lateral resolution

Resolution mainly determined by detector



Synchrotron for nanotomography

Bending magnets

Focusing magnetsInsertion device

(undulators or wigglers)

Bending magnets

•Deviate the beam, close the path

•Produce 2nd generation synchrotron radiation

•Large horizontal divergence, wide beam

•Limited brightness but real white beam

Insertion device (undulator or wiggler)

•Produce 3rd generation synchrotron radiation

•Small divergence, narrow beam

•High brilliance, pink beam (~1keV)



Synchrotron for nanotomography



Synchrotron beamline for nanotomography

Bleuet et al. APL, 2008



Acquisition in tomography

Unknown Sample

X-ray source

2Dradiographs

Rotationaxis



Acquisition in tomography

Radiographs = Rθθθθ (x,z)x

z

x

θ

Sinogram = Sz (x, θθθθ)



Tomographic reconstruction

x

θSinogram = Sz (x, θθθθ)

x

y



2D��3D

� Parallel beam

� Just repeat the same thing at another altitude !

� Perform reconstruction of all slices

� And stack them all.

x

z



Scanning chemical imaging



Energy dispersive

detector

Scanning tomography for chemical

imaging

� EELS-like scanningCa K-α Fe K-α Zn K-α

X-r

ay

beam

Sample

I0

It



Reconstruction in XFCT

� Inverse problem complex

Beam

∫∫∫∫==== duuspSignalMeasured Zcefluorescen ),(. )(αααα

)(nAttenuatio 0EBA→→→→

)(nAttenuatio mCB E→→→→

A

B

C

Get it from the transmissiontomography

UNKNOWN !!

Energydispersive

detector



XFCT Reconstruction

� Correction from attenuation not directly possible� Problem critical for elements not accessible to measurement (Z<15)

� Algorithmic solution� Optimal estimation of attenuation maps by combination of transmission,

fluorescence and Compton tomographies

Golosio et al., J. Appl. Phys. 2003

)(~)x()( ZceFluorescen Z

p ρρρρ Spatial distribution of the mass density of each chemical elements

)x(156

)(∑∑∑∑<<<<<<<<Z

Zoptρρρρ Spatial distribution of the mass density of elements between Z=6 and Z=15



Solid Oxide Fuel Cell

Bleuet et al. Trends in Analytical Chemistry, 2010



An AFM tip….

Bleuet et al. Rev. Sci. Instr., 2009



(Powder) Diffraction tomography

� Goal

� Be sensitive to the crystalline phases �Scanning diffraction tomography

� Principle

� Focus x-rays as small as possible

� Raster scan (y,ϕ) while recording powder diffraction image

� Move the sample up and proceed to a new raster scan



Ny××××Nωωωω Diffraction Images

1cm

y

ωωωω

Sum Sinogram

Sum Pattern

Azimuthal Integrations

Ny××××Nωωωω Diffraction Patterns

Fit2d software

Phase Sinograms

ωωωωy

PyMcasoftware

ReconstructionCapillary

Calcite

Ferrite

Cubic

sp3

25µµµµm

y

x

Bleuet et al, Nature Materials, June 2008



Direct analysis : Reconstruction for each d-spacing

Glass capillary (111) (220)

x

y

d-spacing (channels)

Alvarez-Murga, Bleuet, J-L. Hodeau et al. J. Appl. Cryst. 44, 1( 2011).



Tomography & Sensitivity

� Minor phases are lost !

2D slice of 3Dsample

1D diffraction profile

X-ray beam



Reverse analysis in 2D

x

2θθθθ

x

y

Axial (x,y) reconstruction

(x, 2θθθθ) reconstruction



Reminder: electrons & x-rays

� Hard x-rays (15keV or more)� Deep (sub)-µµµµm resolution

� Wavelength @30keV=41.3pm

� Huge lever arms, Complex optics

� Quasi-unlimited penetration power� “Attenuation length”

� http://henke.lbl.gov/optical_constants/atten2.html

� Electrons� nm resolution

� Wavelength @200kV=2.5pm

� Efficient optics

� Aberration limits the resolution to 50pm

� Very limited penetration power� “Mean Free Path”, “Stopping power”

� “Continuous Slowing Down Approximation range”

� http://xdb.lbl.gov/Section3/Sec_3-2.html



Electron tomography

� Similar to x-ray tomography

� Technique widely used by biologists

� For hard condensed matter� Sample preparation required

� 200nm max

� Principle� Collection of e- at large scattering angles

� Low diffraction contrast

� Projection requirement fulfilled



Aberration corrected micorscopes

� FEI TITAN1 (2005/2007)

� FEG gun

� Cs probe aberration correction (STEM)

� TEM, STEM (BF/DF et HAADF) imaging, holography, tomography

� Gatan filter Tridiem (STEM-EELS, EFTEM)

� EDX detector

� 2 CCDs 2k x 2k

� FEI TITAN Pico

� High brilliance XFEG gun

� Monochromator (dispersion 0,1 eV)

� Cs probe and imaging aberration correction (STEM et TEM)

� TEM, STEM (BF/DF et HAADF) , holography, tomography

� Gatan Quantum Filter (STEM-DualEELS, EFTEM)

� EDX detector

� 2 CCDs 2k x 2k



71 HAADF images (@ 300 kV with α = 15 mrad)acquired between -73 and +70°

Gate all around transistors

10nm TiN

3nm Hf02

15nm SiGe

SiN hard mask

SiGe wires



Destructive tomography

� Reasons for a sample to be precious � Only one sample exists (e.g. cultural heritage)

� Sequential analyses of the same sample by different probes

� X-rays and electrons radiation damage…

� Samples may often be destroyed� Microelectronics: billions of device per wafer

� Materials science: “random” ROI

� Alloys, polymers, cements

� Biology: selection of a few cells out of a large population of cells



From Uchic and HolzerMRS Bulletin 2007

« Slice and view » FIB nano-tomography



Zeta FIB column (Ga+)• Resolution 4 nm @ 30 kV / 0.1 pA• Accelerating voltage 1 kV to 30 kV• Current 0.1 pA to 45 nA @ 30 kV

Four channelGas Injection System• TEOS, C, Pt deposits• Liquid, solid state

and gas precursors

Gemini FEG SEM columnResolution 1.1 nm @ 20 kV and 2.5 nm @ 1 kV Accelerating voltage 100 V to 30 kVProbe current 4 pA to 20 nA

In-lens SE and EsBGood low-voltage performance

EDX (Brucker)

SE and SI

STEMBright field & dark field

Eucentric stageX 100 mm - Y 100 mm - Z 43 mmZ’ 10 mm - Tilt -10/+60°- R 360°6 motorized axisLoad lock 4”

QBSE

Detectors :





� Robust technique

� Works well both for large volumes @ nm resolution� No reconstruction, no local tomography

� Orientation & chemical contrast � SE & BSE images at low voltage

� Great potential� FIB-SEM � 3D morphology

� FIB-SEM-EDX � 3D chemical imaging

� FIB-SEM-EBSD � 3D grain & strain imaging



� Why sub-nanometer tomography in micro & nanoelectronics ?� 32 nm node (2010), 22nm (2011), 16nm (2013), 11nm (2015)

� Devices are now 3D !

� Multigate, tri gate, gate all around transistors

� Seeing, locating and identifying atoms in 3D becomes important

� Only 3D analytical technique available� Atom Probe Tomography (ancestor of Field Ion Microscopy)

Sub-nanometer tomography

DrainGate

Source



� Principle � Cryogenically-cooled needle shaped sample

� UHV + trace gas

� Progressive evaporation of surface atoms

� Pulsed voltage

� Recent evolutions� Position sensitive detector

� 2D depth resolved mapping

� Pulsed LASER

� Time of flight spectrometer

� Chemically sensitive

� 10 millions of atoms !

Atom Probe Tomography

Miller & Forbes, Mat. Charac. (2009)



Atom Probe Tomography

� Spatial resolutions� X,Y resolution ~ 0.1-0.3nm

� Z resolution ~0.3-0.5nm

� Detection efficiency ~60%

� Volume ~200,000nm3/hr

� FoV ~ 2000nm



Towards Nanometer3

Resolution

Probedvolume

100nm 1µµµµm

1000mm3

1000 µµµµ m3

1000nm3

Hard x-rayMicrotomography

Towards hard x-rayNanotomography

Electron & FIBNanotomography

Atom ProbeTomography

10nm1 A

5µm

Si

Cu Void

γγγγ-ray and neutronTomography

1mm

10nm



� Georg Haberfehlner (CEA-LETI)

� Matt Smith (MIT)

� Romain Quey (ex-CEA-LETI, now CNRS)

� Gérard Delette (CEA-LITEN)

� Jérôme Laurencin(CEA-LITEN)

� Pierre-Henri Jouneau(CEA-INAC)

� Adeline Grenier(CEA-LETI)

� Vincent Delaye

� Peter Cloetens (ESRF)

� Heikki Suhonen (ESRF)

� Jean-Louis Hodeau (CNRS)

� Frédéric Souchon (CEA-LETI)

� Patrick Leduc (CEA-LETI)

� Julien Bertheau (ST Microelectronics)

� Jean Charbonnier (CEA-LETI)

� And the Noesis & Lafarge organizers

Thanks to…

Documents

CEA-Leti / DTSI / SCMC MINATEC Campus, 17 rue des … · CEA-Leti / DTSI / SCMC MINATEC Campus, 17 rue des Martyrs 38054 GRENOBLE Cedex 9 ... Technology ©CEA. All rightsreserved