Conventionally known semiconductors
such as Si and GaAs have a band gap of 1.12 eV and 1.43 eV ,respectively.
In electronic devices, they are not suitable for high temperature
condition because of their relatively narrow band gap. Diamond
has 5.5 eV band gap which is so wide that this material can
potentially be used in high temperature condition. Furthermore,
it has high mobility, high breakdown voltage and high thermal
conductivity. So it can be used widely in engineering application.
In this thesis, the syshesis of diamond films using thermal
filament CVD method is reported. The mixture of ethyalcohol
and hydrogen is used as the source in atmospheric pressure.
This hydrocarbon-hydrogen mixture is dissociated by the thermal
generated from tungsten filament. To determine the optimum condition
of diamond film growth, the controlling of source concentration
and substrate temperature is studied. The surface morphology
of the films are characterized by X-ray diffraction and Raman
spectroscopy, respectively. Boron doped diamond films are fabricated
at various borontrioxide concentration. Basic electrical properties
of the films such as semiconductor type, resistivity, conductivity,
carrier concentration, carrier mobility and activation energy
are measured. In addition, the electrical properties of metal-diamond
film contact and p-i junction are studied. Finally, high operating
temperature Schottky diodes are fabricated and their properties
are reported.
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