Shot Noise Modeling in Metal-Oxide-Semiconductor Field Effect Transistors under Sub-Threshold Condition

We have developed a new simulation methodology for predicting shot noise intensity in Metal-Oxide-Semiconductor Field Effect Transistor (MOSFET). In our approach, shot noise in MOSFETs is calculated by employing the two dimensional device simulator MEDICI in conjunction with the shot noise model of p-n junction. The accuracy of the noise model has been demonstrated by comparing simulation results with measured noise data of p-n diodes. The intensity of shot noise in various n-MOSFET devices under various bias conditions was estimated beyond GHz operational frequency by using our simulation scheme. At DC or lowfrequency region, sub-threshold current dominates the intensity of shot noise. Therefore, shot noise is independent on frequency in this region and its intensity is exponentially depends on VG, proportional to L, and almost independent on VD. At highfrequency region above GHz frequency, on the other hand, shot noise intensity is frequency dependent and is quite larger than that of low-frequency region. In particular, the intensity of the RF shot noise is almost independent on L, VD and VG. This suggests that high-frequency shot noise intensity is decided only by the conditions of source-bulk junction.