Effect of Drift Region Doping and Coulmn Thickness Variations in a Super Junction Power Mosfet: a 2-d Simulation Study

In this paper, a power SJMOSFET (Super junction MOSFET) transistor is simulated using PISCES-II, a 2-D numerical device simulator. The doping densities and device dimensions are chosen so as to simulate a typical device structure. These simulations are aimed at understanding the device physics through various electrical quantities like potential distribution, electric field distribution, and electron concentrations etc. in different regions of the device both in on/off states. The effects of doping variations in the ‘n’ and ‘p’ pillars of the SJMOSFET along with the variations in the column thickness of the device were investigated. Various results obtained reveal that device having equal doping in the n and p pillars and having equal width of these pillars gives the best results. The current density is maximum and the charge imbalance is minimum for this case, however the breakdown voltage increases when the width of the n pillar is decreased.