Jm. Schneider et al., Hydrogen uptake in alumina thin films synthesized from an aluminum plasma stream in an oxygen ambient, APPL PHYS L, 74(2), 1999, pp. 200-202
We describe the hydrogen uptake during the synthesis of alumina films from
H2O present in the high vacuum gas background. The hydrogen concentration i
n the films was determined by the H-1(N-15, alpha gamma)C-12 nuclear resona
nce reaction. Furthermore, we show the presence of hydrogen ions in the pla
sma stream by time-of-flight mass spectrometry. The hydrogen content increa
sed in both the film and the plasma stream, as the oxygen partial pressure
was increased. On the basis of these measurements and thermodynamic conside
rations, we suggest that an aluminum oxide hydroxide compound is formed, bo
th on the cathode surface as well as in the film. The large scatter in the
data reported in the literature for refractive index and chemical stability
of alumina thin films can be explained on the basis of the suggested alumi
num oxide hydroxide formation. (C) 1999 American Institute of Physics. [S00
03-6951(99)02302-5].