Physical Insights on Steep Slope FEFETs including Nucleation-Propagation and Charge Trapping

Physical Insights on Steep Slope FEFETs including Nucleation-Propagation and Charge Trapping ■

Y. Xiang, A. S. Verhulst, Bertrand Parvais, N. Horiguchi, G. Groeseneken, J. Van Houdt, M. Garcia Bardon, Md Nur K. Alam, M. Thesberg, B. Kaczer, P. Roussel, M. I. Popovici, L. A. Ragnarsson, B. Truijen

Abstract ■

We present a kinetics-based analysis of the steep slope operation of ferroelectric (FE) FETs built on (i) a statistical multidomain nucleation-propagation mechanism of FE polarization switching and (ii) charge trapping in the high- K FE oxide. With a hardware-validated compact model we predict the change in hysteresis direction, the steep slope and the transient behaviors observed in our I-V measurements on Hf0 5Zr0 5O2-based planar n-FEFETs. We find that the proposed field-independent propagation is essential in explaining the measured reverse-sweep steep slope and transient current drift. Furthermore, the model suggests that a higher polarization and accordingly a larger I-V hysteresis are induced upon increased trapping. Finally, we show that for hafnia-based FE oxides, reliability engineering of defect band is needed for obtaining steep slope in scaled logic-FEFETs.