Analytical Threshold Voltage Model Including Effective Conducting Path Effect (ECPE) for Surrounding-Gate MOSFETs (SGMOSFETs) With Localized Charges

On the basis of 2-D potential analysis performed while taking into account the effective conducting path effect, a new analytical model for threshold voltage in cylindrical surrounding-gate MOSFETs (SGMOSFETs) that contain localized charges is presented. From the 2-D Poisson's equation based on a parabolic potential approximation, a simple and accurate analytical expression for the threshold voltage is derived. The proposed model is validated using a 3-D device simulator, and good agreement is obtained for various device dimensions and charge distributions. This model can be used to investigate hot-carrier-induced degradation of SGMOSFETs.