COMPONENTS FOR SURFACE ANALYSIS - SPECS

1 SURFACE ANALYSIS Vacuum SURFACE ANALYSIS Computer Technology COMPONENTS System Software Technology C O M P O N E N T S F O R S U R F AC E A N A LYS I S. X-ray Monochromator FOCUS 500. High energy dispersion High efficiency Ellipsoidal crystal design AI K and Ag L X-rays Focused X-ray flux FOCUS 500. Monochromator The ellipsoidal monochromator FOCUS 500 The FOCUS 500 utilizes an ellipsoidal X-ray operates according to Bragg s Law of X-ray mirror. The mirror is composed of a mono- diffraction. A single wavelength of X-rays is lithic backing support with precisely oriented reflected from a quartz single crystal mirror at atomic bonded crystal plates.

2 The mirror has a specific angle of reflection. a 500 mm Rowland circle diameter which offers a high X-ray energy dispersion. The large SURFACE area of the quartz crystals defines a solid angle of sterad for X-ray diffraction and hence leads to an intense X-ray flux from the monochromator for high efficiency. A manipulator with precision temperature BIS. ELLIPSOIDAL GEOMETRY compensated drives provides three degrees Using BIS the sample is irradia- ted by an electron beam with The ellipsoidal mirror images of motion (two directions of tilt and one of a narrow energy distribution.)

3 A point source located at the ellipsoidal mirrors focus translation, completely decoupled from each The interaction between the on the sample perfectly. incident electrons and the solid other) for accurate mirror positioning. involves the direct deceleration of the incident electron with A moveable aluminized polymer window the simultaneous emission of An X-ray monochromator provides Bremsstrahlung. The electron (shutter) is provided on the monochromator then occupies a previously the following advantages: empty state above the Fermi housing for differential pumping or to shield level.

4 The probability of Brems- strahlung emission is related Higher resolution the crystal assembly during sputtering. to the density of unoccupied states. Higher sensitivity The monochromator can be used to perform The FOCUS 500 provides Lower background Bremsstrahlung Isochromat Spectroscopy the capability to measure the intensity of a single X-ray No satellites (BIS) with a retrofittable attachment to wavelength while scanning the energy of the electron Reduced sample damage the standard equipment. beam. Focused X-ray spot Typical Performance The lens modes of the PHOIBOS analyzer series are optimized to give unsurpassed resolution and intensity performance with the FOCUS 500.

5 X-ray monochromator. ZOOM. In the non-focusing mode some line broadening occurs due to the finite width of the X-ray spot. In the focusing mode the broadening due to the source is negligible. C o m p e t e n c e i n S u r f a c e A n a l y s i s FOCUS 500. X-ray Source The X-ray source XR 50 M is specially chromator resolution is limited by the rocking designed for use with the monochromator. curve width of the quartz crystals only. The power supply features high power opera- ROCKING CURVE. tion up to 600 W. The reflected intensity versus the angle of incidence With the FOCUS 500 the Bragg condition of the X-rays for a given crystal type is known as for Ag L X-rays is satisfied in second order.

6 The rocking curve. The twin anode (Al/Ag) allows a changeover For quartz crystals the rocking curve width is from monochromatized Al K to Ag L excita- about 160 meV. tion with only minor adjustments and without breaking the vacuum. ELECTRON OPTICAL SIMULATION. The Ag L photon energy of eV means that the FOCUS 500 can excite higher energy The figure above shows an electron optical core levels and Auger series. In addition, the simulation of the focusing lens in the X-ray higher electron energy increases the ANALYSIS source XR 50 M. depth. This lens can focus the electrons that impinge Each anode can be operated in a focusing on the anode and produce a variable X-ray spot or non-focusing mode.

7 Due to the small size. Both anodes (Al/Ag) can be operated in source size in the focusing mode the mono- focusing or non-focusing mode. Spectral Data 4000. 3500 MonoXPS. PHOIBOS 150 MCD-9 W 4f 3000 WSe2 sample (h = eV). Intensity (counts). FWHM = eV. 2500 Se 3d 2000. 1500. 1000. 500. 0. 58 57 56 55 54 53 52 37 36 35 34 33 32 31. Binding Energy (eV). The main core levels of a layered crystal of WSe2 The diagram shows the Ag 3d5/2 peak. The inherent are shown. The resolution is limited by the quality electron energy resolution was about 220 meV. of the uncleaved sample SURFACE .

8 The X-ray source was run in focus mode. 20000. 18000 MonoXPS. 16000 PHOIBOS 100 MCD-5. Si 1s Si sample (h = eV). 14000. Si KLL. Intensity (cps). 12000. 10000. 8000. 6000. 4000. 2000. UNSURPASSED RESOLUTION. 0. 1900 1800 1700 1600 1500 1400 1300 1200 The width of the Fermi edge demonstrates the high Binding Energy (eV) resolution capability of the FOCUS 500 monochromator. With the photon energy of eV Ag L new This spectrum shows the Fermi edge of Ag core levels can be excited for Al, Si, P, S, Cl, Br to at T=300 K. The widths of the edge is 210 meV. Ru, Tm to Pt, Au, Hg, Pb and Bi.

9 (16 % to 84 %). C o m p e t e n c e i n S u r f a c e A n a l y s i s FOCUS 500. Technical Data Monochromator FOCUS 500 (all dimensions in mm).. Single crystal Quartz (1010). Crystal area 100 200 mm2. Crystal manipulator independent roll, pitch and focus Rowland circle 500 mm Port length 177 mm Chamber diameter < 310 mm Shutter Moveable X-ray window Bakeout temperature 150 C (monochromator remains outside the blanket). Mounting DN 100 CF. Differential pumping optional BIS optional Weight 40 kg X-ray source Anode material Dual anode (Al/Ag). Modes of operation Focusing and non-focusing mode Spot size on anode Focusing mm2.

10 Non-focusing 4 Voltage Up to 15 kV. Power Al 150 W / focusing mode 400 W / non-focusing mode Power Ag 260 W / focusing mode 600 W / non-focusing mode 11/06 SPECS reserves the right to alter technical specification without further notice. Manipulator 3-axis, micrometer drives Weight 17 kg Resolution SCD MCD-5 MCD-9. COUNT RATE SPECIFICATION. The PHOIBOS analyzer series will exceed Al K , 15 kV, 400 W, non-focusing mode with the FOCUS 500 monochromator the eV 60,000 300,000 600,000 values specified in the table (values are given 120,000 600,000 1,200,000 in cps for the Ag 3d5/2 signal above the back- Al K , 15 kV, 150 W, focusing mode ground).