The fabrication and characterization of high temperature Terahertz emitters, and DNA-sensitive transistors based on silicon-germanium and silicon carbide materials.

摘要

In recent years, new applications in Terahertz (THz) imaging, spectroscopy, ranging and telecommunication had initiated huge research interest in THz emitting devices. There were few suitable sources available, however, in the THz frequency range (1-10 THz). Thus more powerful terahertz sources were strongly desired, especially with higher operating temperatures. This dissertation described two THz emitting devices based on Si and SiC materials that demonstrated much higher operating temperatures than what was previously published.;Dry etching with xenon difluoride (XeF2) was a well-known process for the isotropic removal of silicon. The etching of silicon germanium alloys with XeF2, however, had not been investigated. Here, the XeF2 dry etching of SiGe-alloys was characterized versus composition and XeF2 partial pressures. It was found that the etch rates showed a strong dependence on Ge content of the etched materials. The roughness of the etched surfaces was also investigated. This study provided etch rates versus process conditions and etched surface roughness, which were useful information for accurately fabricating SiGe-based structures and devices.;Label-free detection of DNA molecules via electronic methods were also investigated in this dissertation. A device that was similar to conventional metal-oxide-semiconductor (MOS) was described. The current-voltage characteristic was used to investigate the behavior of this Si-based field effect device with DNA solutions of various concentrations and molecular states deposited on the sensing region.