In-plane-gate flexible single-crystalline silicon thin-film transistors with high-k gate dielectrics on plastic substrates

Flexible single-crystalline silicon in-plane-gate thin-film transistors (TFTs) with high-k gate dielectrics on plastic substrates have been demonstrated in this letter. The high-k Nb2O5-Bi2O3-MgO (BMN) ceramic has been deposited as gate dielectric layer by magnetron sputtering at room temperature. ∼200 nm Si nanomembrane as the device active layer has been transferred onto the flexible substrates. An in-plane-gate structure has been employed for the flexible TFTs, to achieve high control ability and low leakage current. The flexible TFT demonstrates ∼106 on/off ratio, ∼230 cm2v-1s-1 electron field effect mobility, and only ∼nA leakage current. The capacitances of the in-plane-gate structure are measured and analyzed to better understand the channel control mechanism of the flexible TFTs with high-k gate dielectrics. Mechanical bending tests have been conducted and the underlying mechanism for the device performance variations has been discussed. The flexible TFTs show great potential for the applications in high performance, large area and high integrated flexible circuits.