Drain current modelling of double gate-all-around (DGAA) MOSFETs

Abstract

Here, an analytical modelling of drain current is presented for double gate-all-around (DGAA) MOSFETs. A common feature in all the multi-gate (MG) MOSFETs is that the channel charge in the sub-threshold regime is proportional to the channel cross-sectional area; whereas, the inversion charges above threshold locate near the Si/SiO2 interfaces and are proportional to the total gated perimeter of the channel body. This distinctive feature introduces the notion of equivalent charge and has been widely used to model the drain current of any arbitrary non-classical MOSFET architecture. The authors have extended the aforementioned quasi-approach to model the drain current of DGAA MOSFET. The total gated perimeter of DGAA MOSFET is mapped by the gated perimeter of two GAA MOSFETs with different radii for the calculation of surface inversion charges above threshold. The currents obtained from two GAA MOSFETs are summed up to obtain the current of DGAA MOSFET. I–V characteristics and transconductance of the device for various physical parameters are compared and analysed with the numerical simulation results obtained from Visual-TCAD of Cogenda Int.