Mapping of the electronic work function anisotropy of RF sputtered molybdenum thin film electrodes for piezoelectric devices

• Published in: Current applied physics 2021, 21(1), , pp.58-63
• Main Authors: Sharma, Neha, Kumar, Ravi, Jayabalan, J.
• Format: Article
• Language: English
• Subjects: KPFM; Molybdenum thin films; RF magnetron Sputtering; Work function; 물리학
• ISSN: 1567-1739; 1878-1675
• DOI: 10.1016/j.cap.2020.10.010

Amplitude modulated Kelvin probe force microscopy was performed on molybdenum (Mo)-thin films deposited on Si(001) substrates by RF magnetron sputtering. Evolution of film microstructure from amorphous to crystalline was observed with increasing RF power from 25 W to 200 W. Spatial mapping of work function across the film surface revealed that the Mo-thin film deposited at 200 W possesses an average work function ~4.94 ± 0.06 eV while higher values were observed at lower RF powers. The genesis of distinct periodic changes in work function is attributed to the formation of the surface dipole layer associated with the adsorbates of different polarities (O2−/OH− or H+). A phenomenological model is also presented to elucidate their effect. [Display omitted] •Molybdenum-thin film electrodes deposited by magnetron sputtering at different RF powers.•Amplitude modulated Kelvin probe force microscopy measurements.•Mapping of electronic work function anisotropy on molybdenum-thin film surface.•Variation in work function due to the presence of electronegative/electropositive adsorbates.•Model depicting the formation of surface dipole layer due to the presence of adsorbates.