Investigation and Modeling of Multifrequency CV characteristics for 10-nm Bulk FinFETs at Cryogenic Temperatures

In this work, multifrequency capacitance-voltage characteristics have been investigated from 300K to 10K for high-k HfO2-based 10-nm bulk n-channel FinFETs. The dispersion observed in the accumulation region for the multifrequency capacitance characteristics with respect to temperature is explored taking into consideration the temperature dependence of border traps, series resistance, tunneling current, and the substrate time constant. It was found that the temperature-dependent dispersion arises due to the increase in the substrate time constant with temperature reduction. Multifrequency conductance measurements were performed from 300K to 10K to experimentally investigate the variation of substrate time constant with temperature. Furthermore, the temperature dependence of the accumulation region surface potential quotient is also explored in order to examine the direct tunneling current. Finally, modifications to existing accumulation region BSIM-CMG 110.0.0 compact model equations are proposed to include the low-temperature dispersion effects.