Design and performance optimization of thin film tin monoxide (SnO)/silicon electron-hole bilayer tunnel field-effect transistor

This paper presents a novel thin film electron-hole bilayer tunnel field-effect transistor based on an oxide semiconductor tin monoxide (SnO)/silicon heterojunction (TFBTFET), which delivers low-power high switching speed characteristics. SnO has an intrinsic p-type profile, which provides desirable properties for application in thin film tunnel transistors and liquid crystal displays. Unlike conventional tunnel field-effect transistors with limited horizontal tunneling direction, the tunneling window of the TFBTFET is created along the channel length in the vertical direction, leading to significantly increased drain drive current. The results demonstrate that the steep transition of the current from off-state to on-state delivers subthreshold swing of 5 mV/dec with on-state current of 3.03 x 10(-5)(A/mu m), off-state current of 5.1 x 10(-14)(A/mu m) and on/off current ratio of 5.94 x 10(8). The impact of critical scaling of design parameters on the electrical performance of the device is comprehensively investigated by calculating the coefficient of variation (CV), expressed as a percentage, of the main electrical measures. The 2D variation contour of required voltage for the onset of band-to-band tunneling is computed as a function of the top and bottom gate work function to determine an optimum value yielding superior electrical performance. Moreover, CV analysis reveals that the off-state current and subthreshold swing are relatively insensitive to the variation in gate length, which indicates the potential for application of the device in integrated circuits with superior efficiency.