Lowering the activation temperature of Ti-Zr-V non-evaporable getter films by removing surface carbon contamination: an in situ XPS study

FIGURE 1: XPS raw data of the (a) C1s, (b) Ti2p, (c) Zr3d and (d) O1s-V2p lines, respectively, after an annealing and in situ oxygen plasma treatment (50 W for 15 min) and annealing at four different temperatures: 100 °C, 130 °C, 150 °C and 200 °C. FIGURE 2: XPS raw data of the (a) C1s, (b) Ti2p, (c) Zr3d and (d) O1s-V2p lines, respectively, of an as-received sample, after an in situ argon (80%)/oxygen (20%) plasma treatment (60 W for 2h) and after an annealing at 150 °C overnight. FIGURE 3: XPS raw data of the O1s-V2p lines corresponding to different sequential plasma and annealing cycles performed at 150 °C overnight in all cases. FIGURE 4: Normalized O1s area ratio as a function of annealing at 100, 130, 150 and 200 °C, respectively. FIGURE 5: XPS raw spectra corresponding to the O1s core level of Ti-Zr-V films undergoing plasma and 150 °C annealing cycles: (a) 50 W oxygen plasma for 15 min and (b) 60 W argon/oxygen plasma for 2 h. The intensity of the spectra corresponding after annealing have been multiplied by a factor of two. FIGURE 6: XPS raw data of the (a) C1s, (b) Ti2p, (c) Zr3d and (d) O1s-V2p lines, respectively, of a sample exposed to argon (80%)/oxygen (20%) plasma (60 W for 2 h) after an annealing at 150 °C overnight and the same sample stored in UHV (≈ 1×10-9 mbar) for 5 days. Spectra have been normalized to their maxima. FIGURE 7: XPS raw data of the Si2p lines corresponding to as-received samples and after different plasma treatments: oxygen plasma (50 W, 15 min), argon/oxygen (50 W, 2 h) and (60 W, 2 h). FIGURE S2: Experimental and simulated (using SESSA software) survey XPS spectra. FIGURE S3: XPS raw data of the C1s core level of an as-received Ti-Zr-V film, after an exposure to a first 50W oxygen plasma cycle for 15 min, after an overnight annealing at 150 °C and after a subsequent second 50W oxygen plasma cycle for 15 min. FIGURE S4: XPS raw data of the C1s core level of an as-received sample with the corresponding least-squares fits using the CasaXPS software after a Shirley-type background subtraction using a combination of Gaussian (70%) and Lorentzian (30%) functions under the constraint of identical full width at half maximum (FWHM) for all components. FIGURE S5: XPS raw data of the N1s core level of an as-received sample, after exposure to an argon/oxygen plasma (80%-20%) at 60 W for 2 and after annealing overnight at 150 °C. FIGURE S6: XPS raw data of the (a) C1s, (b) Ti2p, (c) Zr3d and (d) O1s-V2p lines, respectively, after an annealing at 130 °C for 24 h, oxygen plasma treatment (50 W for 15 min), annealing al 200 °C for 1 h and exposure at a base pressure of ≈ 5 × 10-7 mbar for 16 h.