Analytical Analysis of Punchthrough in Burried Channel P-MOSFETs

The punchthrough phenomenon in burried-channel (BC) P-MOSFETs (depletion mode devices) is analysed analytically using the voltage-doping transformation (VOT) technique. The mechanism of punchthrough in a BC-P-MOSFET is shown to be, similarly as in a surface-channel (SC) N-MOSFET, due to the DIBL effect. However in a BC-MOSFET the DIBL effect is shown to be considerably enhanced by the effect of screening of the surface inversion layer of electrons. The new punchthrough current model, an unique up to date, deals correctly with the screening effect and shows high accuracy within a wide range of biases and channel lengths.