Laterally resolved ion-distribution functions at the substrate position during magnetron sputtering of indium-tin oxide films
- Department Solare Energetik, Hahn-Meitner-Institut, Glienicker Strasse 100, D-14109 Berlin (Germany)
During the magnetron sputtering from an indium-tin oxide (ITO) target (76 mm diameter) we measured the ion-distribution functions (IDFs) of energetic ions (argon, indium, and oxygen ions) at the substrate surface using a combination of a quadrupole mass spectrometer and an electrostatic energy analyzer. We obtained the IDFs for argon sputtering pressures in the range from 0.08 to 2 Pa and for dc as well as rf (13.56 MHz) plasma excitation with powers from 10 to 100 W. The IDF measurements were performed both over the target center at a target-to-substrate distance of 65 mm and at different positions along the target radius in order to scan the erosion track of the target. The mean kinetic energies of argon ions calculated from the IDFs in the dc plasma decreased from about 30 to 15 eV, when the argon pressure increased from 0.08 to 2 Pa, which is caused by a decrease of the electron temperature also by a factor of 2. Indium atoms exhibit higher mean energies due to their additional energy from the sputtering process. The total metal ion flux turns out to be proportional to the discharge power and the pressure, the latter dependence being due to Penning ionization of the metal atoms (In and Sn). From the scans across the target surface the lateral distributions of metal, oxygen, and argon ions were derived. In the dc discharge the position of the erosion track is reproduced by increased ion intensities, while it is not the case for the rf excited plasma. The lateral variations of the observed species do not influence the lateral resistivity distributions of the deposited ITO films.
- OSTI ID:
- 21020868
- Journal Information:
- Journal of Vacuum Science and Technology. A, International Journal Devoted to Vacuum, Surfaces, and Films, Journal Name: Journal of Vacuum Science and Technology. A, International Journal Devoted to Vacuum, Surfaces, and Films Journal Issue: 5 Vol. 25; ISSN 1553-1813
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ARGON IONS
DISTRIBUTION FUNCTIONS
EV RANGE 10-100
INDIUM IONS
KINETIC ENERGY
MAGNETRONS
MASS SPECTROMETERS
MASS SPECTROSCOPY
MHZ RANGE 01-100
OXYGEN IONS
PLASMA
SEMICONDUCTOR MATERIALS
SPUTTERING
SUBSTRATES
SURFACES
TAIL IONS
THIN FILMS
TIN OXIDES