Short channel epi-MOSFET model

We show how threshold voltages and the electric field perpendicular to a channel are controlled by varying the thickness of the epi-layer in long epitaxial channel MOSFET devices (epi-MOSFETs). Using our proposal of a two-region polynomial potential distribution and a universal boundary condition that effectively expresses the variation of depletion width along a channel, we calculated the two-dimensional (2-D) potential distribution. We also derived a threshold voltage model for short channel epi-MOSFETs. Our model reproduces the numerical data of sub-0.1-μm gate length devices, and predicts that the short channel immunity of these devices is not as good as predicted by the previous model. However, their performance is superior to that of double-gate SOI MOSFETs.