| Gallium tin zinc oxide (GSZO) is a promising replacement for indium gallium zinc oxide (IGZO) and for potential flexible and transparent thin film transistor (TFT) applications. Some of the areas of practical applications for GSZO TFTs are large and fast liquid crystal displays, and three-dimensional (3D) displays and organic light-emitting-diode displays. The performance of the TFTs is influenced by the presence of the interface trap density. The focus of this thesis is to use capacitance-voltage (C-V) characterization to probe the behavior of amorphous oxide semiconductor (AOS) TFTs and to obtain qualitative information on interface states of GSZO TFTs. Comparisons between different GSZO TFT samples were made and our findings were presented in this work to provide a base and a guideline for further research on AOS TFTs. The GSZO TFTs examined were sputter deposited on silicon with inverted gate configuration and air annealed at 150°C, 250°C or 350°C for 1 hour. The C-V measurement of our GSZO TFTs was carried out at 250 Hz and 1 MHz frequencies. The interface trap density (Dit) was found to be high at the conduction band edge. |
