Four-terminal polycrystalline-germanium thin-film transistors fabricated at 300°C by metal induced crystallization using copper on a glass substrate

Four-terminal (4T) polycrystalline-germanium (poly-Ge) thin-film transistors (TFTs) are fabricated at 300 °C by metal induced crystallization (MIC) using copper (Cu) on a glass substrate. We observed variations in the performance for top gate (TG) and bottom gate (BG) drives, although the gate stacks of both drives are same. This difference results from the quality of the poly-Ge/BG SiO
₂
interface, which is damaged during amorphous-Ge (a-Ge) sputtsring deposition. This indicates that the performance of poly-Ge TFTs can be further improved by optimizing the a-Ge deposition process. Further, such improvement leads to the feasibility of high-performance 4T poly-Ge TFTs on plastic substrates.