Surface Analysis

X-ray Photoelectron Spectroscopy (XPS) is a powerful technique that combines the advantages of chemical and elemental specificity, high surface sensitivity and quantitative analysis of the surface composition.  XPS technique is based on the photoelectrical effect. Under Ultra High Vacuum (UHV), an X-ray source (with a given photon energy, hn) is used to illuminate a sample surface. Photoionized electrons from valence and core levels are then analyzed by an electron analyzer. The X‐ray induced photoelectron spectrum is then obtained as photoelectrons intensity versus their kinetic energy.

• Kratos Axis Ultra DLD specifications

– Monochromated X-ray source Al Kα X-radiation (1486.6 eV)
– Dual anode Al Kα X-radiation (1486.7 eV) and Mg Kα X-radiation (1253.6eV)
– Hybrid magnetic and electrostatic lens system Hemispherical analyzer
– Area of analysis selection via aperture: 300 µm ´ 700 µm, 110 µm, 55 µm, 27 µm or 15 μm
– Electron detection and counting with a 2D Multi Channel Plate – delay line detector (DLD).
– 4-axis sample stage (x, y, z, θ) allowing angle-resolved studies for non-destructive depth profiling
– Temperature controlled sample stage with a range of -100 to 600 °C
– 5 keV Ar+ source for depth profiling and surface cleaning
– Charge neutralization system – analysis of insulators to prevent sample charging

• Sample submission

– Samples that can be analyzed by XPS include: Catalyst powders, polymers, steels and metallic alloys, thin films, solid foam…
– Maximum sample sizes (l x w x h): 80 mm x 30 mm x 4 mm
– Samples must be stable down to 2.10^-10 mbar
– Sample holders are adapted for ToF-SIMS and LEIS analysis

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 high mass resolution, an unlimited mass range and a parallel detection of all ions.

The unique Qtac energy analyser was designed by IONTOF. This analyser has an acceptance over the full azimuth providing a high sensitivity and high mass resolution.

Low Energy Ion Scattering (LEIS) is a surface sensitive analytical technique used to characterize the chemical and structural makeup of materials. LEIS involves measuring the kinetic energy of dispersed ions, after sending a monoenergetic beam of these ions onto a surface to characterise it. LEIS probes the elemental composition of the outermost atomic layer of a material and provides static depth profiles of the outer 10 nm of surfaces. Its extreme surface sensitivity and quantitative nature make it a powerful tool for studying the relationships between surface chemistry and surface related phenomena such as wetting, adhesion, contamination, and thin film growth.

• IONTOF – Qtac 100 specifications

– Primary ion beam: He⁺, Ne⁺, Ar⁺
– Beam spot size around 10 µm
– Hydrogen and oxygen plasma for surface cleaning
– Typically scan area from 1 x 1 mm² to 2 x 2mm² (for negligible damage)
– Time-of-Flight Mass Filter to improve the elemental detection limits.

• Qtac 100 key features

– 3000 times higher sensitivity than conventional LEIS instrument
– Quantitative, Elemental characterization of the top atomic layer
– Spectroscopy and imaging capabilities
– Analysis of rough and non-conductive materials

Samples can be treated under reactional stream (H₂, CO, NO, O₂… or light alcohol vapors) up to 900 °C, then transferred under vacuum towards XPS, ToF-SIMS or LEIS analysis chambers. Possibility to connect a mass spectrometer to analyze the residual gas output.