Self-aligned metal double-gate junctionless p-channel low-temperature polycrystalline-germanium thin-film transistors with a thin germanium channel on a glass substrate

Polyaystalline-germanium (poly-Ge) thin-film transistors (TFTs) are good candidates for next-generation TFTs for use in the backplane of flat-panel displays (FPDs). This is due to their superior electrical properties compared to those of Si and oxide semiconductors. However, poly-Ge shows a strong p-type characteristic; thus, it is not easy to reduce the leakage current using a single-gate (SG) structure. In this study, self-aligned metal double-gate (MeDG) junctionless (JL) p-channel (p-ch) low-temperature (LT) poly-Ge TFTs were fabricated on a glass substrate using a 15-nm-thick solid phase crystallized (SPC) poly-Ge film. Additionally, SG JL p-ch LT poly-Ge TFTs with 15-nm-thick SPC poly-Ge films were fabricated as reference TFTs. The self-aligned MeDG JL p-ch LT poly-Ge TFT shows superior performance compared to that of SG JL p-ch LT poly-Ge TFT.