Capacitance-voltage characteristics of Si and Ge nanomembrane based flexible metal-oxide-semiconductor devices under bending conditions

摘要

Metal-oxide-semiconductor (MOS) device is the basic building block for field effect transistors (FET). The majority of thin-film transistors (TFTs) are FETs. When MOSFET are mechanically bent, the MOS structure will be inevitably subject to mechanical strain. In this paper, flexible MOS devices using single crystalline Silicon (Si) and Germanium (Ge) nanomembranes (NM) with SiO_2, SiO, and Al_2O_3 dielectric layers are fabricated on a plastic substrate. The relationships between semiconductor nanomembranes and various oxide materials are carefully investigated under ten-sile/compressive strain. The flatband voltage, threshold voltage, and effective charge density in various MOS combinations revealed that Si NM-SiO_2 configuration shows the best interface charge behavior, while Ge NM-Al_2O_3 shows the worst. This investigation of flexible MOS devices can help us understand the impact of charges in the active region of the flexible TFTs and capacitance changes under the tensile/compressive strains on the change in electrical characteristics in flexible NM based TFTs.