Investigation of substrate-dependent characteristics of SnO2 thin films with Hall effect, X-ray diffraction, X-ray photoelectron spectroscopy and atomic force microscopy measurements
B. Yea et al., Investigation of substrate-dependent characteristics of SnO2 thin films with Hall effect, X-ray diffraction, X-ray photoelectron spectroscopy and atomic force microscopy measurements, JPN J A P 1, 38(4A), 1999, pp. 2103-2107
SnO2 thin films of 100 nm in thickness were prepared on glass and alumina s
ubstrates with targets-facing type sputtering apparatus to investigate the
substrate-dependent characteristics of the films. The sensitivity of the fi
lms is measured in flammable gas atmosphere (hydrogen, butane and methane,
5000 ppm), and it revealed that the SnO2 films on alumina substrates showed
better sensitivity for all introduced gases than the films on glass substr
ates. Hall effect, X-ray diffraction (XRD), X-ray photoelectron spectroscop
y (XPS) and atomic force microscopy (AFM) measurements were performed to cl
arify the difference of the sensitivity, and it is concluded as follows: 1)
The variation of carrier concentration of the films on alumina substrates
is larger than those on glass substrates when they are exposed to flammable
eases. 2) The structure of the films on alumina substrates is similar to t
hat of SnO2 powder. 3) The film on an alumina substrate contains more oxyge
n impurities than that on a glass substrate, which can be considered to cau
se the large variation of carrier concentration. 4) Surface area of the fil
ms on alumina substrates is wider than that of the films on glass substrate
s.