Characterization of thin MoO3 films formed by RF and DC-magnetron reactive sputtering for gas sensor applications

18th International Summer School on Vacuum, Electron and Ion Technologies

Yordanov, R.^1 ; Boyadjiev, S.^1,2 ; Georgieva, V.^3 ; Vergov, L.^3

Department of Microelectronics', Technical University of Sofia, 8 Kliment Ohridski Blvd., 1756 Sofia, Bulgaria^1

Department of Inorganic and Analytical Chemistry', Budapest University of Technology and Economics, Hungarian Academy of Sciences, 4 Müegyetem rakpart, H-1111 Budapest, Hungary^2

Acad. G. Nadjakov Institute of Solid State Physics, Bulgarian Academy of Sciences, 72 Tsarigradsko Chaussee, 1784 Sofia, Bulgaria^3

关键词: As-deposited state;    DC magnetron reactive sputtering;    Direct current magnetron sputtering;    Long-term measurements;    Quartz resonators;    Radio frequencies;    Sensing property;    Sensor applications;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/514/1/012040/pdf
DOI  :  10.1088/1742-6596/514/1/012040

来源: IOP

【 摘 要 】

The present work discusses a technology for deposition and characterization of thin molybdenum oxide (MoOx, MoO3) films studied for gas sensor applications. The samples were produced by reactive radio-frequency (RF) and direct current (DC) magnetron sputtering. The composition and microstructure of the films were studied by XPS, XRD and Raman spectroscopy, the morphology, using high resolution SEM. The research was focused on the sensing properties of the sputtered thin MoO3films. Highly sensitive gas sensors were implemented by depositing films of various thicknesses on quartz resonators. Making use of the quartz crystal microbalance (QCM) method, these sensors were capable of detecting changes in the molecular range. Prototype QCM structures with thin MoO3films were tested for sensitivity to NH3and NO2. Even in as-deposited state and without heating the substrates, these films showed good sensitivity. Moreover, no additional thermal treatment is necessary, which makes the production of such QCM gas sensors simple and cost-effective, as it is fully compatible with the technology for producing the initial resonator. The films are sensitive at room temperature and can register concentrations as low as 50 ppm. The sorption is fully reversible, the films are stable and capable of long-term measurements.