Fabrication and characterisation of zinc oxynitride for thin film transistors
Hanbin Ma
a
, Guangyu Yao
a
, Augusto Kunrath
b
and Arokia Nathan
a
a
Electrical Division, Engineering Department, University of Cambridge, U.K.
b
MVSystems LLC, U.S.
E-mail:
In this work, zinc oxynitride semiconductor material is produced by a reactive rf magnetron
system. This single metal compound material shows different properties over the well-studied
multimetal compound materials such as indium-zinc-oxide and zinc-tin-oxide. In order to
investigate the mechanism of growth competition between the hexagonal zinc oxide (ZnO)
and cubic zinc nitride (Zn
3
N
2
), experiments based on different processing conditions are
carried out. UV-Vis spectroscopy is used to determine the approximately ratio between the
wide bandgap zinc oxide (> 3.2 eV) and narrow bandgap zinc nitride (< 2 eV). It has been
reported that nitrogen will compress the oxygen vacancies in zinc oxide, and therefore
enhance the stability. It is found that zinc is very sensitive to oxygen. To achieve a nitrogen
rich film, high N
2
/O
2
ratio (even more than 100:1) and high rf power is used. XRD is used to
characterize the crystal structure of the films. In addition, thin film transistors are fabricated
with a multiple-chamber cluster system comprising of reactive sputtering, ALD and PECVD.
Thin film transistors with different structures and different dielectric/semiconductor
interfaces will be presented.
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