Verification of influence of tail states and interface states on sub-threshold swing of Si n-channel MOSFETs over a temperature range of 4–300 K

We experimentally characterize sub-threshold swing ( SS ) of Si n-channel MOSFETs with a substrate boron concentration of 2 × 10 16 cm −3 as a function of drain current ( I DS ) and temperatures from 4 to 300 K in order to verify the validity of the physical model of SS . The minimum SS are obtained experimentally at 4 K of around 4 mV dec −1 . The physical model including mobile band tail states and localized interface states with a Gaussian distribution, proposed by Beckers at el., is employed to represent the experimental SS from 4 to 300 K. The impact of each parameter included in the physical model on the SS behavior is examined by changing the value of the parameters in simulation. It is found that the proposed physical model can quantitatively represent experimental SS in a wide range of I DS and temperature under a given set of the parameters regarding the band tail states and the interface states. This finding indicates the validity of the present physical model and the correctness of the physical picture.