Performances of a Capacitorless 1T-DRAM Using Polycrystalline Silicon Thin-Film Transistors With Trenched Body

Polycrystalline silicon thin-film transistors (TFTs) can be improved by integrating DRAM on chip. However, the TFT´s poor capacitance means that traditional DRAMs are infeasible, because they require a capacitor. An alternative, the one-transistor DRAM (1T-DRAM), is promising because it avoids the capacitor by instead storing the logical value as holes trapped in the body region. This letter proposes the use of a trenched body in a TFT to construct a 1T-DRAM. Previously, we have shown that a trenched body reduces the leakage current of a TFT. In this letter, we now show that the trenched-body TFT also works well as a 1T-DRAM device. It has a strong back-gating effect and a programming window that is more than twice as large as that of the conventional TFT.