Investigation of electrical characteristics on surrounding-gate and omega-shaped-gate nanowire FinFETs

In this paper, electrical characteristics of small nanowire fin field-effect transistor (FinFET) are investigated by using a three-dimensional quantum correction simulation. Taking several important electrical characteristics as evaluation criteria, two different nanowire FinFETs, the surrounding-gate and omega-shaped-gate devices, are examined and compared with respect to different ratios of the gate coverage. By calculating the ratio of the on/off current, the turn-on resistance, subthreshold swing, drain-induced channel barrier height lowering, and gate capacitance, it is found that the difference of the electrical characteristics between the surrounding-gate (i.e., the omega-shaped-gate device with 100% coverage) and the omega-shaped-gate nanowire FinFET with 70% coverage is insignificant. The examination presented here is useful in the fabrication of small omega-shaped-gate nanowire FinFETs. It clarifies the main difference between the surrounding-gate and omega-shaped-gate nanowire FinFETs and exhibits a valuable result that the omega-shaped-gate device with 70% coverage plays an optimal candidate of the nanodevice structure when we consider both the device performance and manufacturability.