Deposition of crystals from the plasmas of ZrO/sub 2/, HfO/sub 2/, ThO/sub 2/, and CeO/sub 2/
Deposition occurs onto a cathode from an oxide plasma generated inside a hollow oxide anode by the mechanism called the electrolysis of plasma. The temperature of the cathode is usually over 2000 /sup 0/C during deposition. Deposits attain fairly large crystalline sizes (about 0.3 mm) in spite of their high deposition rates. And besides, some unusual crystals are formed. For the deposition from ZrO/sub 2/, HfO/sub 2/, and ThO/sub 2/ plasmas, the deposition rate, growth rate, and the current efficiency increase with the plasma current (0.4--8 A) and with feeding O/sub 2/ gas into the plasmas. On the other hand, heating a cathode externally or feeding Ar gas into them leads to the reduction of those rates, the current efficiency, and yield. The maximum growth rate from the ThO/sub 2/ plasma is 8.4 ..mu..m/sec. Yields exceed 90% in general. Mass-spectrometric analyses showed that the main depositing ion species is ZrO/sup +/ for the deposition from the ZrO/sub 2/ plasma. Deposits obtained are usually black oxides, whose O/M (M=Zr, Hf, and Th) ratios are 1.95, 1.95, and 1.64, respectively. The deposits from ZrO/sub 2/, HfO/sub 2/, and ThO/sub 2/ plasmas are monoclinic ZrO/sub 2/ with precipitates of metallic ..cap alpha..-Zr, monoclinic HfO/sub 2/ with a small amount of unknown hexagonal crystals (whose lattice parameters are a=3.17 and c=5.02 A), and a mixture of fcc ThO/sub 2/ and Th, respectively. When O/sub 2/ gas is fed into those plasmas, transparent oxide crystals of stoichiometric composition are formed. The deposits from a CeO/sub 2/ plasma are the black oxides whose O/Ce ratios are 1.53 on the average. Contrary to the phase diagram of the Ce-O system, they show x-ray structures of fcc crystals whose lattice parameter varies from 5.506 to 5.411 A.
- Research Organization:
- Institute of Atomic Energy, Kyoto University, Kyoto, Japan
- OSTI ID:
- 5920864
- Journal Information:
- J. Appl. Phys.; (United States), Vol. 50:10, Issue 10
- Country of Publication:
- United States
- Language:
- English
Similar Records
Crystal Phase Distribution and Ferroelectricity in Ultrathin HfO 2 –ZrO 2 Bilayers
Plasma enhanced atomic layer deposition of HfO{sub 2} and ZrO{sub 2} high-k thin films
Related Subjects
CERIUM OXIDES
DEPOSITION
HAFNIUM OXIDES
THORIUM OXIDES
ZIRCONIUM OXIDES
ANODES
EFFICIENCY
ELECTRIC CURRENTS
ELECTROLYSIS
GASES
OXYGEN
PLASMA HEATING
VERY HIGH TEMPERATURE
ACTINIDE COMPOUNDS
CERIUM COMPOUNDS
CHALCOGENIDES
CRYOGENIC FLUIDS
CURRENTS
ELECTRODES
ELEMENTS
FLUIDS
HAFNIUM COMPOUNDS
HEATING
LYSIS
NONMETALS
OXIDES
OXYGEN COMPOUNDS
RARE EARTH COMPOUNDS
THORIUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
ZIRCONIUM COMPOUNDS
360201* - Ceramics
Cermets
& Refractories- Preparation & Fabrication