tesi R. Miscioscia.pdf - EleA@UniSA

Introduction 7
structure has been designed and developed on the basis of chapter 2
and 3 considerations.
The study was addressed by characterizing the devices by
measuring the static curves of output characteristics and gate-drain
(input-output) trans-characteristics. Activation energy of the mobility
of charge carriers in thermal measurements have also is extracted in
the aim to investigate charge transport at dielectric-channel interface.
The tools employed in the proposed analyses are based on the
model parameters of field effect transistors (mobility, threshold
voltage, saturation current) and non-ideal factors linked to leakage
currents but also gate-field dependent mobility models have been
studied and introduced to model the presence of trap levels in
disordered semiconducting mediums like in our case.
Among the adopted models, particular attention was paid to the
extraction tools, modeling and analysis of gate leakage. The
introduction of an equivalent circuit of the studied TFTs to separate
intrinsic behaviors from non ideal-drifts has been performed. The
developed simple model has been applied to characterize the thermal
annealing effects on complete devices and to make consideration
about the drift of gate currents.
Specific data concerning the development of manufacturing
processes of OTFT were provided showing the routes that have
enabled it to increase integration level and overall performance of
studied transistors.
The survey on the major sources of non-idealities related to the
dielectric-dielectric interface and channel modeling and
characterization and analysis has led to the identification of
morphological and process factors that can influence the mobility and
current saturation in OTFT considered. Finally, an innovative
inorganic dielectric deposited by liquid-phase using sol-gel process
has been introduced to reveal specific characteristics compared to the
data acquired so far. This was made possible by the methods of
extraction of physical parameters such as current channel the energy
of Meyer-Neldel without which it would not be possible to identify
these correlations and the found exceptions.