Insights into unconventional behaviour of negative capacitance transistor through a physics-based analytical model

Abstract

The present work investigates key attributes of metal–ferroelectric–metal–insulator–semiconductor (MFMIS) cylindrical nanowire (NW) transistor through a physics-based analytical model. The proposed NW MFMIS negative capacitance model is developed by solving the baseline short channel NW model coupled with one-dimensional Landau’s equation while considering the radial dependency of electric field in the ferroelectric, a key feature for NW architecture. Contrary to the expected behaviour of a short channel MOSFET, the analytical framework successfully captures the unconventional effects such as an increase in the threshold voltage, lowering of subthreshold swing, and a negative value of drain-induced barrier lowering with gate length downscaling in MFMIS cylindrical NW devices. Also, the impact of ferroelectric thickness, spacer induced polarization charge density, remnant polarization and coercive field on the unconventional short channel effects have been examined. The influence of different ferroelectric materials (Al–HfO2, Gd–HfO2, Y–HfO2, and HZO) on the extent of internal amplification has also been investigated. The developed model provides new insights into the functioning and optimization of NW MFMIS architecture for facilitating hysteresis-free high internal voltage amplification with sub-60 mV/decade swing.