Low Temperature and Silicon Thickness Influences on the Threshold Voltage of Double-Gate MOSFETs Considering a Charge Based Extraction Procedure

This work studies the influence of the temperature and the fin width (silicon thickness) on the threshold voltage of lightly doped double-gate MOSFETs. The evaluation was performed using tridimensional simulations, device measurements and model. The threshold voltage was defined considering the classical double derivative method and a charge based one, and the results were compared to an analytical model. The charge based definition has shown a better concordance with the analytical model for the influence of both temperature and fin width. The surface potentials extracted at the threshold condition have also exhibited that the charge-based criterion for threshold voltage definition results in closer values to those expected analytically. The variation of the threshold voltage with the temperature is overestimated if it is extracted using the double derivative method in comparison to the charge-based one. Experimental results confirmed the predictions obtained through simulations and model.