Regional Platform of Surface Analysis

Scientifics and technicals managers :

Jean-François Paul, Pardis SIMON, Nicolas NUNS et Martine TRENTESAUX.

XPS

XPS KRATOS, AXIS Ultra^DLD (2009)

The AXIS Ultra^DLD provides the latest generation tool for high sensitivity muti-technique electron spectroscopy. Spectra may be acquired in either scanned or rapid un-scanned ‘snapshot’ mode by using the delay-line detector (DLD).

The AXIS Ultra^DLD has the unique capability of parallel imaging using a spherical mirror analyser providing lateral distribution images of elemental and chemical species at the surface.

As with all AXIS spectrometers unrivalled performance on insulators is guaranteed by the use of the coaxial charge neutalisation system

Details of AXIS Ultra DLD components and performance.

VACUUM SYSTEM

Sample analysis chamber (SAC) Stainless steel with double Mu metal screening layer Spherical 267mm diameter, 23 ports (15 line of sight) Ion pump with cryoshroud (220 l/s) Sample treatment chamber (STC) Multiple options offering high flexibility including : Simple load lock and preparation chamber Preparation chamber with additional fast entry lock Catalyst reaction chamber Radial distribution chamber Turbomolecular pump (250 l/s) (oil free option)

X-RAY SOURCES

Dual anode (Mg and Al Kα source) High power Al monochromator 500mm Rowland circle Quartz toroidal backplane

ELECTRON ENERGY ANALYSER

180° hemispherical analyser 165mm mean radius Spherical mirror analyser

SMALL SPOT SELECTED AREA

defined by insertion of aperture into lens column 110um, 55um, 27um and 15um calibrated analysis areas virtual probe deflected over sample by scan plates (sample remains static)

PHOTOELECTRON DETECTOR

MCP stack and delay-line detector Scanned and snapshot spectroscopy modes 2D imaging mode

CHARGE NEUTRALISATION

Fully automatic Coaxial low energy electron source

AUTOMATION

4 axis software and hardware controlled autostage 5 axis software and hardware controlled autostage (optional) Optional fully automatic spot size selection from 15µm to large area

In situ catalysis cell of preparation chamber.

Treatment of the sample under reactionnel stream (H2, CO, NO., O2) for controlled pressure and until T=900°C then transfer in situ towards the chamber of analysis of the spectrometer

VG Escalab 220 XL (1996)

• dual anode (Al-Mg) and monochromator (Al)-Ion gun (noble gases)
• Depth profiling
• Sample cleaning
• Preparation and reactor chambers

XPS main properties

• atomic spectroscopy identifying all the elements (except H)
• binding energies of orbitales sensitive to the chemical environment (notion of chemical shifts)
• in-depth analysis in the10nm range (exponential function) reduced by angular variation
• quantification with use of morphological models
• sensibility in l / 100e of monolayer
• detection of electrons Auger ( XAES)
• depth profile by ionic abrasion
• analysis of the valence band of solids

ISS main properties

• atomic identification of the most superficial coat(layer)
• bad resolution for the elements of high atomic mass
• difficult quantification – need of reference

	In situ catalysis cell of preparation chamber. Treatment of the sample under reactionnel stream (H2, CO, NO., O2) for controlled pressure and until T=500°C then transfer in situ towards the chamber of analysis of the spectrometer
	Transfer vessel fitted on the preparation chamber

TOF SIMS

Ion ToF, Tof SIMS5

Time-of-Flight Secondary Ion Mass Spectroscopy (ToF SIMS) is a very sensitive analytical technique, for many industrial and research applications. This technique uses a pulsed ion beam (here Bi+) to remove both atoms and molecules from the sample surface (< 4 monolayers). The secondary ions removed from the surface are then extracted and accelerated by an electrical field and their masses are then determinate by measuring their time of flight over the analyzer to reach the detector.

The time of flight analysis allowed a very high mass resolution, an unlimited mass range and a parallel detection of all ions.

ToF SIMS applications :

ToF SIMS offers infinity of possibilities to characterize materials, users imagination might be the only limit.

A wide range of industrial and research fields uses ToF SIMS : catalysis, corrosion, polymers, semiconductors, biomaterials, paper, metals, glass, coatings, pharmaceutical ….

The three main modes of analysis are :

• 1) Spectroscopy : High sensitivity in the ppm / ppb range, unlimited mass range, high mass resolution

• 2) Depth profile : Two ion beams operate. While the first beam (Cs or O2) is sputtering a crater, the second beam (Bi+) is progressively analyzing the crater bottom. The depth resolution is better than 1 nm and the sputter speed can be up to 10 µm/h

• 3) Imaging 2D or 3D : ToF SIMS machine offers the opportunity to perform chemical mapping of element or molecules with a high lateral resolution (< 100 nm). By combining depth profile with 2D imaging, it is possible to reconstruct 3D images

Figure 1 : a) ToF SIMS spectrum of Mo-based catalyst in the 107-120 uma range. The isotope cluster calculator (b) confirms that the seven main peaks correspond to Molybdenum oxide

Figure 2 : ToF SIMS depth profile of a Ni/P coating on Ni

Figure 3 : ToF SIMS 2D imaging : Calcium particles are observed on silicon subtract

ION TOF / ToF SIMS V specifications :

Primary gun : Bi, Bi3

Mass Resolution : 104

Mass detection : parallel

Mass range : “unlimited”

Sensitivity : ppm / ppb range

Main application : Static SIMS, Dynamic SIMS

Lateral resolution : < 100nm

Raster precision : up to 1024 x 1024 pixel resolution

Field of view : from µm² to cm²

Sputtering gun : Cs and O2

Depth resolution : ≈ 1nm

Sputter speed : up to 10 µm/h

LEIS

Ion ToF, Qtac100

The Qtac is a high sensitivity low energy ion scattering (LEIS) instrument. It is extremely surface sensitive, providing elemental and structural characterisation of the top atomic layer. This new generation instrument has been developed to include small spot analysis, surface imaging, and both static and dynamic depth profiling. Its unique surface sensitivity makes the Qtac the perfect tool to study surface processes. The Qtac provides valuable information in many production and research areas on materials such as catalysts, semiconductors, metals, polymers, fuel cells, and biomaterials. Key features are :

• 3000 times higher sensitivity than conventional LEIS instruments
• Quantitative, elemental characterisation of the top atomic layer
• Spectroscopy, imaging and depth profiling capabilities
• Time-of-flight mass filtering for improved sensitivity
• Analysis of rough and non-conductive materials