Multi-Level Memory Comprising Only Amorphous Oxide Thin Film Transistors

A multi-level memory circuit with only amorphous oxide thin-film transistors (Ox-TFTs) is proposed. The proposed circuit comprises two Ox-TFTs and a capacitor. The proposed multi-level memory can modulate threshold voltage freely depending on programming voltages. Low leakage current of Ox-TFT enables the proposed circuit to operate as a memory. We measured transfer characteristics of the proposed circuit and investigated the threshold voltage shift by a simple capacitance model. We found that the proposed memory cell can be used as a multi-level memory.