(Invited) Hot Carrier Phenomena in Oxide Thin-Film Transistors

Abstract

We observed hot carrier-induced photon emissions in oxide TFTs with structures of BCE-type and TG-type for the first time in addition to ESL-type. In this paper, the effects of these TFT structures on the hot carrier phenomena are described using TFT characteristics, photon-emission analysis, and TCAD simulation. We observed the degradation of TFT characteristics in BCE-type and TG-type, which was similar to that in Si-based devices, along with the photon emission. In contrast, for the ESL-type, we found the behavior depending on the drain–ESL overlap length. When this overlap length was under 1µm, photon emission and no significant shift of TFT characteristics were observed; however, when it was 3µm, no photon emission and a significant shift of TFT characteristics were observed. Based on the potential distributions near the drain obtained by the TCAD simulation, we propose the degradation mechanism of ESL-type depending on the drain–ESL overlap length.