An Improved Shift-and-Ratio Effective Channel Length Extraction Method for Metal Oxide Silicon Transistors with Halo/Pocket Implants

Abstract

The original shift-and-ratio method tends to significantly over-estimate the effective channel length Leff of metal–oxide–silicon (MOS) transistors with halo/pocket implants because the carrier mobility of the short transistor tends to be smaller than that of the long transistor. A modification of the original method has been tested on both n-channel metal–oxide–silicon (NMOS) and p-channel metal–oxide–silicon (PMOS) transistors fabricated by state-of-the-art complementary metal–oxide–silicon (CMOS) technology. The values of Leff generated by this method are more reasonable than the original shift-and-ratio method with much less computation time involved. The theoretical basis of our method is that the carrier mobility of the short transistor is approximately equal to that of the long transistor when the gate voltage is close to the threshold voltage for state-of-the-art MOS transistors with <2 nm gate oxide.