Quantes XPS/HAXPES spectrometer (ULVAC-PHI)
The Quantes spectrometer is used to analyse the chemical composition of materials by performing both traditional XPS with an AlKα X-ray source (1487eV) and laboratory HAXPES with a CrKα X-ray source (5415eV). The large energy difference between both sources allows collecting data from the sample surface (<10nm for Al) and sub-surface (<30nm for Cr). Both X-ray beams are highly focused (<20µm) on the same sample area, enabling spatially resolved chemical analyses. Non-destructive in-depth measurements can be performed by comparing the results obtained with both sources at the same point.
The Quantes is an XPS instrument designed to pioneer new methods such as laboratory HAXPES providing access to buried critical interfaces or active materials deeply buried under thick capping layers. This technique is rather new and still under development. The use of high energy X-rays with a CrKα source provides access to an extended energy range and thus to new core levels that still need to be identified and documented in terms of chemical bonding states. Moreover, an extensive use of this technique still requires working on quantification.
- Sample size <1cm2, sample height <1cm, no in-situ sample preparation
- AlKα X-ray source: scanning and monochromatic AlKα source (1487eV) with a highly focused beam (∼7.5µm)
- CrKα X-ray source: scanning and monochromatic CrKα source (5415 eV) with a highly focused beam (∼14µm)
- High energy analyser: 180° hemispherical electron energy analyser working in a large energy range (0-5000 eV) optimized for high energy resolution, high angular acceptance and small area XPS sensitivity. The best energy resolution is ∼0.5eV for AlKα (20µm spot) and ∼0.85 eV for CrKα (100µm spot).
- In-situ argon sputtering for surface cleaning, depth profiling or charge compensation: Energy range = 10-5000 eV, maximum beam current >5 µA
- Dual beam charge neutralization using simultaneously low energy electrons and the ion gun for automatic charge compensation of insulating samples
- Base pressure: <1×10-7 Pa provided by turbo molecular pumps, differential pumping during in-situ argon sputtering (P ∼7×10-6Pa)
- Robotic sample handling platform for fully automated transfers between the different chambers
- Fully automated, five axis (X, Y, Z, rotation and tilt), eucentric sample stage combined with in-situ X-rays induced secondary electrons imaging to locate the analysis point
- Nano for Quantum Technologies
- Disruptive Devices
- Advanced Integration
Key Enabling Technologies
- Metrology / Characterisation: Physical
A typical case study is the investigation of typical multi-layers stacks developed for new emerging memory devices. Laboratory HAXPES can be used to gain information about the chemistry of the critical interface between the Ti layer, acting as an oxygen getter, and the thin HfO2 layer, which resistivity can be switched between high and low states by applying a voltage between the top (Pt) and bottom (TiN) electrodes. Measurements done with the CrKα source (5415eV) at 45° and 90° take-off angles show that both the Ti getter and the buried active HfO2 layers can be investigated, in terms of chemical composition and oxidation states.
The use of the Quantes spectrometer is illustrated on several typical cases in the following paper: