Biaxial Strain based Performance Modulation of Negative-Capacitance FETs

In this work, we report device simulations conducted to study the performance of biaxially strained ferroelectric-based negative capacitance FETs (NCFETs). We adopted PbZr0.5 Ti0.5 O3 (PZT) and HfO2 as ferroelectric materials and applied biaxial strain using the first-principles method. It was found that PZT and HfO2 show different trends in the negative capacitance (NC) region under biaxial strain. Biaxial strain strongly affects the NC of PZT, whereas HfO2 is not as susceptible to biaxial strain as PZT. When no strain is applied, HfO2-based NCFETs exhibit a better performance than PZT-based NCFETs. However, the subthreshold slope and ON-state current are improved in the case of PZT-based NCFETs when the compressive biaxial strain is increased, whereas the performance of HfO2 based NCFETs is slightly degraded. In particular, the negative drain-induced barrier lowering and negative differential resistance vary considerably when compressive strain is applied to PZT-based NCFETs.