On the Log-Linear Inversion-Charge Relation for MOSFET Modeling

In this brief, we take a close look at the log-linear inversion-charge relation adopted in several charge-based compact models for MOSFETs. It is shown that the log-linear relation lacks flexibility in fitting the subthreshold characteristics independent of the above threshold behavior. The shortcomings are born out in specific examples comparing the
${Q}_{\text {i}}$
–
${V}_{\text {gs}}$
curves of the log-linear inversion-charge relation to those of the charge-sheet model and the analytic potential model for double-gate (DG) MOSFETs.