Analytical model for subthreshold current in short-channel fully depleted SOI MOSFETs incorporating velocity overshoot

Silicon-on-Insulator (SOI) structures are of great interest for future large scale integrated circuits (LSIs) because parasitic capacitances in devices are reduced, The reduced device capacitances in SOI devices promise a higher speed circuit operation and lower power consumption than the devices fabricated on bulk Si wafers. An accurate model for the substhreshold current ill MOSFET is very important for design of the high speed-low power transistors and circuits for the assesment of the fully depleted SOI technology in comparison to the conventional bulk technology. A new two dimensional model for subthreshold current in fully depleted silicon-on-insulaor metal oxide semiconductor field effect transistor (SOI MOSFET) is developed. The model is based on a 'free inversion areal charge density'm Qm, solutoin of one dimensional. effective gate channel euation and a quasi-two dimensional Poisson's equation in weak inversion considering a modified expression for effective channel velocity and phenomenon of velocity overshoot. The model provides a convenient tool for the design of submicron SOI MOSFETs.