A method for extracting transport parameters in short-channel FETs is presented in the context of the Lundstrom model for quasi-ballistic short-channel FETs. The parameters extracted from measured data are unidirectional thermal velocity, critical length, and mean free path at low and high drain biases. The method is based on an analysis of the channel length dependence of apparent mobility and virtual-source (VS) velocity, which are obtained by fitting the VS model to measured data. Data from (100)-oriented undoped-body extremely thin silicon-on-insulator FETs with neutral stress liners are used to validate the method. Since this method does not assume any theoretical knowledge of band structure parameters, it can be applied to short-channel FETs with any geometry, any channel material, and with unknown levels of channel stress. © 1963-2012 IEEE.