fibs and soft matter materials…structures…efug.imec.be/efug2007_14_milani.pdf · for lasers and...

8.10.2007 EFUG 2007- Arcachon

FIBs and soft matter... materials…structures…

Marziale Milani

Materials Science Dept. & Laboratorio FIB/SEM “BOMBAY”University Milano-Bicocca, Milano, Italy


Summary

Introduction

Organic Crystals

FIB sectioning for metal detection in digestive gland cells of P.scaber (Isopoda, Crustacea)

Post-fabrication processing of Superluminescent Diodes (SLDs)

Dual FIB/SEM systems for plasma facing materials for magnetic thermonuclear fusion

Laser ablation

Results

Caveat

Acknowledgements


What do we mean by soft matter?

1) Complexity 2) Flexibility[P.G. De Gennes – Nobel Lecture 9 December, 1991]• Emergent properties• Order/disorder• Heterogeneous materials and structures• Quantum Phenomena• Nonequilibrium Physics

Where we are going depends on our knowledge, and our knowledgedepends on where we are going…

[Tess Gerritsen – The Surgeon, Ballantine Publish Group 2001]

Tools, samples, questions strategies and researchproblems: solutions and creation


Soft Matter……

HARD MATTER

ColloidalDispersions

LiquidCrystals

Biomatter(proteins, membranes, nucleic acids)

SOFT MATTER

Non-CrystallineSolids

Cristalline Solids (metals, insulators, semiconductors)

cristalline Solidsdefects (point, dislocations, surfaces & interfaces)

Condensed matter systems

AmorphousSolids (glass)

Polymer Solids (glass & rubber)

Quasicrystals

PolymerMelts and Solutions

Coexistent phasesCells,tissues, organsHeterostructuredmaterialsSubmicron sizedmaterials


FIB/SEM is suitable system to investigate soft matter

Imaging with ion- and electron- beam. (ion beam not only as a milling tool)

Soft matter is not always friendly: samples can be... .....insulating, with very rough surfaces, inhomogeneous, and sometimes without additional information.

Strategies to handle all that kind of variety: • use of e-beam for charge neutralization during milling • Low Vacuum for imaging• heavy Pt deposition for surface smoothing • change of milling parameters and of sample orientation to reduce “curtain effects” and for a milling as regular as possible on the trench walls.


Steps and loops in FIB/SEMPrimary beam(s) (and parameters)

Interactions with the sample (surface, subsurface and bulk)

Desired modifications and operations + undesidered modifications(observable and nonobservable)

Not only milling for e-imagingArtifacts

Sample preparation

Secondary particles –output signals

Different detectors (role of relative geometry and scanning operations) Not only imaging

Image reconstructionImage interpretation

Characterization and hypothesis on processes other than those due to primary beams


1-mm Organic Crystals(Rhodamine 590)for Lasers and Non-linear Optics

In literature one can find examples of rhodamine crystals grown from a solution with typical dimensions of less than 5 um.

A larger organic crystals with a linear dimension up to 1 mm have been built by means of a novel preparation protocol with a solution of rhodamine 590 as a starting precursor.

These exceptional large dimensions can pave the way to a direct exploitation of rhodamine crystals, since they might be imbedded inoptoelectronic devices.

Organic Crystals

Some ‘natural polished’ faces are present and they are coplanar to crystal planes.

Edges and ridges of a single crystal point out directions in which the crystal growths after the first nucleation.

Some cracks in the crystal bulk are also evident with a dimension of few tens ofnanometers.

They could not have consequences on optical properties of a such crystal


Organic Crystals

crystal habit fluorescence

one of the three independent N,N’-diethylrhodamine molecules


Ion imaging BSE: morphology and composition

Sectioning

Organic Crystals

Pt deposition


FIB sectioning for metal detection in digestive gland cells of P.scaber (Isopoda, Crustacea)

Presence of metals (Cu, Zn, Ga, Ag) and significant peaks of P, S, and Ca.

The spectrum refers to an ensemble of cells ( B- and S- cells).

EDS spectrum of the section.

A critical part of this analysis is section preparation.

It is fundamental in determining the volume of interaction that generates X rays apart location selection and quality of the section.

Same order of magnitude of the granules size and depth of generation of X-rays suggest the usefulness of a sample with a thickness lower than 1 micron.

FIB role in preparing quasi – lamellae in situ appears therefore promising


FIB sectioning for metal detection in digestive gland cells of P. scaber (Isopoda, Crustacea)

P, Zn, Cu EDX

BSE image

S, Zn, Cu EDX

Ga EDX map


Post-fabrication processing of Superluminescent Diodes (SLDs)

• Edge emitting

• High power

• Broad band

Applications:

• Fiber gyroscopes

• Optical Coherence Tomography

• Short haul comms

• Wavelength division multiplexing

Z

X

Y

Device Geometry

Stripe SLD (S-SLD) Tapered SLD (T-SLD)

FIB manipulation:output facet amorphisation

FIB manipulation:Pt stripes deposited on output facet


Facet Amorphisation - Testing

7.5 x 7.5µm² squares FIB millingIon Beam currents: 50 – 500pADwell Times: 1 – 8µs(secondary electrons imaging)

Nano-Patterning - Testing

Patterning - Testing

Ion Beam current: 100pADwell Times: 0.5 – 1µswith 0.5µs DT milled lines obtained – no Ga droplets(secondary electrons imaging)

Light Corrent Characteristics (LI)

Pulsed operation (5µs, 200Hz)

0

20

40

60

80

100

120

140

160

0 500 1000 1500 2000 2500

current (mA)

outp

ut p

ower

(mW

)

LB72 FIBLB67 (as LB72)LB100 FIBLB73 (as LB100)


Dual FIB/SEM systems for plasma facing materials for magnetic thermonuclear fusion

Carbon fibers

Carbon fibers:

a precursor


Laser ablationA set of Al and Si targets are considered for laser ablation.Electron images, ion images and FIB cross sectioning can be investigated for an impact scenario description.

Si

BSE:A+B

BSE:A-B

Ion image


ResultsOrganic Crystalsactive material shaping and optical cavity preparationFIB sectioning for metal detection in digestive gland cells of P.scaber (Isopoda,

Crustacea)there is the presence of Copper and Zinc in the exposed section, no significant presence of

Iron; Copper content changes with respect to zinc content while moving from bright spots (metal granules) towards dark sites; there is the presence of Gallium in the exposed section;expected contamination by Ga ions is of low level, although detectable; quality of the section is good after a sequence of cutting and polishing (obtained by a decreasing ion beam currents), and the planarity can be appreciated by electron imaging

Post-fabrication processing of Superluminescent Diodes (SLDs) device characteristic and performances geometrically controlled modificationsDual FIB/SEM systems for plasma facing materials for magnetic

thermonuclear fusion material stresses identification and electrical properties characterizationLaser ablationcrater morphology and intermediate processes “zoology”


CaveatHoc ipsum cum consideraveris: illud

quoque tibi occurrat velim: ut átenebrarum ratione seiungasumbram.

Non est umbra tenebrae: sed veltenebrarum vestigium in lumine.

Vel luminis vestigium in tenebris. Velparticeps lucis et tenebrae.

Vel compositum ex luce et tenebris. Velmixtum ex luce et tenebris.

Vel neutrum á luce et tenebris, et abutrisque se-iunctum.

Et haec vel indè quia non sit plena lucisveritas, vel quia sit falsa lux.

Vel quia nec vera nec falsa, sed eiusquod veré est aut falsé,vestigium, etc.

Habeatur autem in proposito. ut lucisvestigium, lucis particeps, lux non plena.

Giordano Bruno Giordano Bruno -- IntentioIntentio Secunda Secunda ““De De umbrisumbris idearumidearum”” (1582(1582))

Mirror effect(s)


F. Tatti FEI Italia (I)

D. Drobne Dept. Biology University of Ljubljana (SLO)

C. Savoia STM-Agrate B. (I)

F. Causa Dept. Electronic and Electrical EngineeringUniversity of Bath (UK)

and……….

in cooperation with

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