Generation-type drain current transients in advanced (down to 50 nm gate length) floating-body, partially depleted silicon on insulator (SOI) metal oxide semiconductor field effect transistors (MOSFETs) are investigated by 2D numerical simulation in weak inversion operation. An original compact analytical model is derived for the pure transient weak inversion operation and validated on both elementary and realistic 2D structures. The proposed subthreshold transient compact model allows accurate prediction of the influence of the generation lifetime, surface velocity (or interface state density), oxide thickness, and substrate doping on the floating-body-related transient behavior and duration, which is essential for advanced transistor optimization and subsequent circuit applications. Moreover, our model is a unique, robust tool for the electrical characterization of submicrometer SOI transistors because it allows the carrier lifetime extraction independently of the channel carrier mobility and device effective gate length. Finally, the model is successfully used in high-temperature operation for drain current transient prediction and generation lifetime extraction. (C) 2004 The Electrochemical Society.