Vincent FAVRE-NICOLIN Univ. Grenoble Alpes & CEA Grenoble/INAC/SP2M XDISPE (ANR JCJC SIMI )

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1 Vincent FAVRE-NICOLIN Univ. Grenoble Alpes & CEA Grenoble/INAC/SP2M XDISPE (ANR JCJC SIMI ) Imagerie par diffraction des rayons X de nano-objets uniques pour la photonique et l'électronique X-ray Diffraction Imaging of Single nanostructures for Photonic and Electronic applications

2 XDISPE: X-ray Diffraction Imaging of Single nanostructures for Photonic and Electronic applications Photonics GaAs Nanowires With InAs quantum dots Electronics Transistor Silicon-On-Insulator (SOI) lines Motivation: the (relative) variability of physical properties is usually higher for nanostructured objects (top-down and bottom-up) The goals of the XDISPE project are : To continue developing X-ray coherent diffraction imaging to quantify strain on a nanometer scale in 2 and 3D To apply this technique to materials for photonic and electronic applications, which use or exhibit anisotropic strain fields, and to link it with their physical properties

3 Collaborators & Funding Projet ANR XDISPE (JCJC-2011-SIMI10) Imagerie par diffraction des rayons X de nano-objets uniquespour la photonique et l'électronique X-ray Diffraction Imaging of Single nanostructures for Photonic and Electronic applications Budget: 250 k Durée mois : 10/ /2015 CEA Grenoble (INAC + LETI): M. Elzo-Aizarna, O. Mandula, J. Eymery, F. Mastropietro S. Baudot, F. Andrieu, J. Claudon, J. Bleuse, J-M. Gérard, P-H. Jouneau ESRF ID1: (Long Term Project , ANR XDISPE+MECANIX) D. Carbone, T. Metzger, T. Cornelius, P. Boesecke, A. Diaz, T. Schülli, G. Chahine

4 Structure, Strain in Nanostructures Electronic applications Strain affects/tunes the carrier mobility STRAIN n-mosfet 200 nm Photoemission from individual quantum dots STRAIN Photonic applications Size (and strain) changes the photoemission energy No point/linear defects allowed Need accurate size & strain determination : Spatial resolution 1-10 nm Elastic strain resolution << 1 %

5 Structure, Strain in Nanostructures catalyst/wire Interface facets SEM Coherent e- diffraction: Nature Materials 7 (2008), 308 P. Bayle-Guillemaud (CEA/INAC)

6 Structure, Strain in Nanostructures catalyst/wire Interface facets SEM Coherent e- diffraction: Nature Materials 7 (2008), 308 (remaining) advantages of X-ray diffraction Chemical sensitivity (resonant scattering) Strain sensitivity small displacements on large scales (>50nm) Non destructive (*) Atomic-resolution transmission electron microscopy works best on small samples (homogeneous field of view < ~50nm) Study many nano-objects / nano-crystals P. Bayle-Guillemaud (CEA/INAC)

7 X-ray Nanobeams X-ray beam NanoObject KB Mirror, or Be CRL or FZP detector 3D reflections in reciprocal space X-ray beams can be focused down to less than 100nm => single nano-objects/grains can be illuminated Monochromatic X-ray nanobeams (Coherent) diffraction Polychromatic X-ray nanobeams Micro-Laue diffraction

8 Nano-diffraction: resolution 1) Scanning X-ray diffraction => resolution ~ beam size 2) Coherent X-ray diffraction => hyper-resolution diffraction FT-1 (requires phasing) Si nanowire Ø 95 nm Si nanowire Ø 95 nm

9 How far down can we go with nanobeams?.. using the Bragg geometry J. Synchrotron Rad. (2009). 16 Biermanns et al GaAs Ø ~ 600nm Phys. Rev. B 79, (2009) Diaz et al InAs Ø ~ 150 nm Phys. Rev. B 79, (2009) Favre-Nicolin et al Si Ø ~ 95 nm

10 Small angle vs Bragg coherent diffraction imaging 2i π ku A ( k ) FT [Ω( r )e ] Simulated nanowire w/insertion - 2% strain along x

11 Small angle vs Bragg coherent diffraction imaging 2i π ku A ( k ) FT [Ω( r ) e ] Simulated nanowire w/insertion - 2% strain along x SAXS

12 3D strain reconstruction 2i π k u A( k ) FT [ Ω( r ) e ] Measuring the CDI on at least 3 independent reflections reconstruct the full 3D displacement field inside the nanocrystal => Access to the full strain tensor Newton et al., Nat. Mater. 9 (2010),

13 Key idea: coherent diffraction in Bragg condition allows to image: The size & shape of the object Any departure from the ideal lattice of that object (strain, dislocation, antiphase boundary,...) => change in e-density or atomic displacements

14 Strained Silicon-On-Insulator (ssoi) lines 225 nm 70 nm Strained Si Strained Si period: 1μm SiO2 ssoi lines: J. Appl. Phys. 105, (2009)

15 ssoi lines : FEM simulation 225 nm 70 nm Strained Si Strained Si period: 1μm SiO2 ssoi lines: J. Appl. Phys. 105, (2009) (113) Uz Simulation (FEM / S. Baudot) (displacements relative to a bulk Si1-xGex lattice) U1-10 Need for accurate strain determinaion in individual SOI lines : Hruszkewycz et al, Nano Lett. 12, 5148 (2012) Shi et al, New J. Phys. 14, (2012)

16 Diffraction of a single ssoi line Incoming beam Q(113) y <110> (113) (113)Si Bragg Scattered beam Reflection x <110> 70 nm 220 nm Phys. Rev. Lett. 111 (2013),

17 Diffraction on single ssoi lines (1-13) Full scattering from a single image (scattering plane is ~ parallel to Ewald's sphere) ssoi lines // scattering plane Phys. Rev. Lett. 111 (2013),

18 Diffraction on single ssoi lines : simulation Simulations from FEM model reproduce well the recorded intensity => direct refinement of displacement field vs. the intensity? Phys. Rev. Lett. 111 (2013),

19 Partial coherence & FZP X-rays X-rays Simulated amplitude & phase at focal spot, for an ideal point source Ideal spot is smaller than the 200x70 nm^2 SOI line Phys. Rev. Lett. 111 (2013),

20 SOI Line, Partial Coherence & FZP X-rays Id01 Undulator source, 160(h) x 40(v) µm^2 Partially coherent illumination Ideal point source We cannot close down the slits before the FZP because it would increase the beam width and illuminate neighboring SOI lines. Use of partial coherence : Flewett et al, Opt. Lett. 34, 2198 (2009) Clark & Peele, Appl. Phys. Lett. 99, (2011) Clark et al, Nat Commun 3, 993 (2012)

21 Diffraction on single ssoi lines : refinement Partial coherence does not allow a direct inversion of the diffraction data 1) Use a parametric description of the atomic displacements 2) refine against experimental diffraction data NB: 10^5 atoms + 2^16 points in reciprocal space + 40 incoherent point source => use GPU (graphical card) for faster calculations See PyNX up to 3.5x10^11 reflections.atoms/s J. Appl. Cryst. 44, 635 (2011)

22 Single ssoi line: partial coherence & FZP t=0s - Source modeled as incoherent point sources - Effect : blurring of the X-ray coherent scattering - Corrects the reconstructed deformation from the phase gradient of the incoming beam Phys. Rev. Lett. 111 (2013),

23 Single ssoi line: beam-induced relaxation T=0 s Phys. Rev. Lett. 111 (2013),

24 Single ssoi line: beam-induced relaxation T=0 s T=800 sec Phys. Rev. Lett. 111 (2013),

25 Single ssoi line: beam-induced relaxation T=0 s T=800 sec T=1600 sec Phys. Rev. Lett. 111 (2013),

26 Single ssoi line: beam-induced relaxation T=0 s T=800 sec T=1600 sec T=2900 sec Phys. Rev. Lett. 111 (2013),

27 Single ssoi line: beam-induced relaxation T=0 s T=800 sec T=1600 sec T=2900 sec The SOI line relaxes as the Si / SiO2 interface evolves due to the strong X-ray beam Polvino et al, Appl. Phys. Lett. 92, (2008) Phys. Rev. Lett. 111 (2013),

28 Single ssoi line: partial coherence & FZP t=800s - Source modeled as incoherent point sources - Effect : blurring of the X-ray coherent scattering - Corrects the reconstructed deformation from the phase gradient of the incoming beam Phys. Rev. Lett. 111 (2013),

29 Single ssoi line: partial coherence & FZP t=1600s - Source modeled as incoherent point sources - Effect : blurring of the X-ray coherent scattering - Corrects the reconstructed deformation from the phase gradient of the incoming beam Phys. Rev. Lett. 111 (2013),

30 Single ssoi line: partial coherence & FZP t=2900s - Source modeled as incoherent point sources - Effect : blurring of the X-ray coherent scattering - Corrects the reconstructed deformation from the phase gradient of the incoming beam Phys. Rev. Lett. 111 (2013),

31 Single ssoi line: time-dependent relaxation Displacement fields uz T=0 s 1.05 T=800 s uz 0.60 (nm) T=1600 s 0.15 T=2900 s Phys. Rev. Lett. 111 (2013),

32 Single ssoi line: time-dependent relaxation T=0-0.6 Strain field : εzx T=800 s 0.0 (%) T=1600 s 0.8 T=2900 s Phys. Rev. Lett. 111 (2013),

33 Photonic GaAs nanowires with an InAs insertion 200 nm Micro-PL Photonic nanowires for quantum cryptography Single photon emission from InAs QD in GaAs nanowire Wavelength & polarisation depends on QD size & location J. Claudon et al., Nature Photonics 4 (2010), 174

34 Photonic GaAs nanowires with an InAs insertion 500nm Sample synthesis: MBE + lithography + etching => ~1.7 ML of InAs in GaAs J. Claudon et al., Nature Photonics 4 (2010), 174

35 GaAs nanowire with a single-layer InAs insertion 1.7 ML InAs 500nm

36 GaAs nanowire with a single-layer InAs: Ptychography Split peak: InAs layer Ptychography : coherent diffraction images with shifting illumination (> 60% overlap) Allows to reconstruct entire object Also reconstruct X-ray probe

37 GaAs nanowire with a single-layer InAs QD: Ptychographic reconstruction 500nm Δφ ~1.2 radian => Δd~0.26 Å => sensitivity of Coherent Bragg Imaging

38 GaAs nanowire with a single-layer InAs QD: Probe reconstruction

39 GaAs nanowire with a single-layer InAs QD: Probe reconstruction Amplitude Phase

40 GaAs nanowire with a single-layer InAs 3D coherent diffraction 500nm Distortion of axial symmetry = signature of QD?

41 GaAs nanowire with a single-layer InAs 3D coherent diffraction => 3D inversion Beam Ab initio reconstruction: good shape of beam*probe Not good enough for QDinduced strain => try model-based minimization 500nm

42 Conclusion Coherent Bragg Imaging: Reconstruct objects smaller than 100 nm (~ limit for light scatterers like Si) Stacking fault structure / individual defects Deformation field (2D/3D) Towards heterogeneous materials Model fitting more versatile than pure ab initio phase retrieval InAs/GaAs nanowires: Full 3d reconstruction Combined micro-pl and 3D location of InAs quantum dots Silicon-on-Insulator Lines: Accurate deformation field (sensitivity ~0.05Å) Follow (slow) in-situ relaxation

43 Projects Coherent X-ray Imaging: Continue algorithms development X-ray ptychography software library available ( InAs/GaAs nanowires: Reconstruct more nanowires Confirm using 3D microscopy (FIB3D, e-tomo) Study correlation between stress and PL properties Strained semiconductor Lines: Next experiment in February: study the variability of deformation along strained SOI lines Study III-V devices

44 Collaborators & Funding Projet ANR XDISPE (JCJC-2011-SIMI10) Imagerie par diffraction des rayons X de nano-objets uniquespour la photonique et l'électronique X-ray Diffraction Imaging of Single nanostructures for Photonic and Electronic applications Budget: 250 k Durée mois : 10/ /2015 CEA Grenoble (INAC + LETI): M. Elzo-Aizarna, O. Mandula, J. Eymery, F. Mastropietro S. Baudot, F. Andrieu, J. Claudon, J. Bleuse, J-M. Gérard, P-H. Jouneau ESRF ID1: (Long Term Project , ANR XDISPE+MECANIX) D. Carbone, T. Metzger, T. Cornelius, P. Boesecke, A. Diaz, T. Schülli, G. Chahine