Research of manufacturing, characterization and sensor applications of sic schottky diodes

Schottky diodes have become an indispensable material for metal-semiconductor technology, thanks to the increasing interest in electronics since the 19th century. The rapid proliferation of solar cells and electric vehicles, in particular, has increased the demand for this material. Our aim in this thesis is to investigate the structure, electrical, and gas-sensing properties of Schottky barrier diodes. In our study, Schottky barrier diodes were produced by coating various metals onto a commercially available 4H SiC wafer using the DC sputtering method. Al was coated on one side for ohmic contact, and metals such as Ti, Ni, Pt, and Ag were coated on the other side to produce different types of Schottky barrier diodes. The DC and AC electrical properties of Al/4H-SiC/Metal (Ti, Ni, Pt, Ag) Schottky barrier diodes were investigated depending on temperature, and hydrogen gas tests were conducted. SEM, EDX, and AFM images were also taken for structural analysis of the 4H SiC wafer. When we examined the current-voltage (I-V) and semi-logarithmic I-V graphs drawn from the measurement data, we observed that the 4H SiC-Ti device exhibited symmetrical Schottky behavior. It was understood that the Al-4H SiC-Pt device operated unilaterally and exhibited Schottky diode properties; the Al-4H SiC-Ni device behaved like a Schottky diode at low temperatures and exhibited ohmic behavior at high temperatures; and the Al-4H SiC-Ag device exhibited Schottky diode behavior at all temperatures. Furthermore, data obtained from hydrogen gas measurements of SiC Schottky diodes were discussed. When the hydrogen sensing properties of the Al-4H SiC-Ni device were examined, it showed a sensor behavior that was not very high at 1% hydrogen concentration.