Effect of vacuum annealing on transparent SnO
x
thin films produced by sputtering of
SnO/Sn composite target
Cheol Kim
1
, Yonghyun Won
1
, Sungdong Kim
2
, Sarah Eunkyung Kim
1
*
1
Graduate School of Nano-IT Design, Seoul National University of Science and Technology,
Korea
2
Department of Mechanical System Design Engineering, Seoul National University of Science
and Technology, Korea
*
Corresponding author
The electrical and structural properties of tin oxide (SnO
x
) thin films have been widely studied for
many different applications such as gas detective materials, transparent electrodes, transparent device,
protective coatings, and solar cells. N-type SnO
x
thin films have a relatively large band gap of 3.6 eV
and a higher exciton binding energy of 130 meV, which becomes an excellent candidate for conductive
electrode or optoelectronic devices, while p-type SnO
x
thin films are a promising candidate for
homojunction diodes or transparent thin film transistors due to a large hole mobility and high optical
transparency. In this study, we have fabricated transparent SnO
x
thin films using rf reactive magnetron
sputtering with a SnO/Sn (9:1at%) composite target, and examined the effects of vacuum annealing on
the electrical, structural, and optical properties of transparent SnO
x
thin films.
The films were deposited
on a borosilicate glass substrate under working pressure of 0.67Pa and rf power of 50W and at 100
℃
substrate temperature. The oxygen partial pressure (P
O2
= O
2
/Ar+O
2
) was varied from 0% to 9%.
Subsequently a vacuum annealing was performed at 300
℃
for 1 hour.
Both X-ray photoelectron
spectroscopy and X-ray diffraction were carried out for structural analysis, and van der Pauw Hall effect
measurement was performed for electrical analysis. In addition, UV/VIS spectroscopy measurements
were carried out for optical analysis. We have obtained both stable n-type and p-type SnO
x
thin films
produced by rf reactive magnetron sputtering of a SnO/Sn composite target. The vacuum
annealing in
this study seems to enhance an electrical carrier concentration of
SnO
x
thin films
, but reduce its mobility due
to some rearrangement and growth of polycrystals. Annealing effect plays a key role in improving native
defects in transparent SnO
x
thin films.
PS2 7
-201-
