Four-terminal polycrystalline-silicon thin-film transistors fabricated by nickel metal-induced crystallization and hafnium oxide dielectric on a glass substrate

摘要

Self-aligned four-terminal (4T) low temperature poly-Si TFTs with hafnium oxide (HfO2) gats dielectric were fabricatsd using nickel (Ni) metal-induced crystallization (MIC) on a glass substrate. The top gate (TG) and bottom gate (BG) were composed of HfO2 and SiO2 dielectric, respectively. We compared their performances under TG drive, BG drive, and connecting double gate mode. It was observed that the TG drive demonstrated a low off current under strong negative BG voltage, but it showed a high off current under positive BG voltage. This result demonstrated that the quality of the poly-Si/BG SiO2 interface was inferior compared to that of the TG SiO2/poly-Si interface due to the segregation of a high concentration of Ni impurities at the poly-Si/BG SiO2 interface.