Oxide Based Field Effect Transistors for Large Area Radiation Detection Electronics

Abstract

Large-area electronics are considered to be a potential improvement to radiation detectors due to their low cost when compared to conventional systems. Currently, low-cost solutions cannot be achieved using conventional silicon technology. On the other hand, metal-oxide semiconductor-based thin-film transistors have shown great potential for large-area electronics. This potential is mostly due to the low processing temperature, and relatively simple fabrication methods when compared to Si-based technology. However, challenges in implementing oxide-based circuits still exist. For example, the deposition of the gate dielectric layers is at these low temperatures, which might result in a less than ideal gate dielectric with a higher oxide trap density; detrimental to the overall TFT performance and stability. Other aspects are the quality of the oxide semiconductor as well as the type of device to be fabricated (MOSFET, and MESFET). In this dissertation, the design and development of highly stable oxide-based field-effect transistors take place. The achieved performance and stability are by careful control of the metal-oxide-semiconductor deposition parameters. Moreover, several process integration strategies for ZnO-based preamplifiers and ultra-violet (UV) photodetectors appear. The radiation detectors show high sensitivity and relatively fast response to UV. A model to explain the increased stability of the resulting devices is also introduced.