With the constant reduction of the transistor dimensions, new transport mechanisms in the conduction channels must be taken into account, as the quasi-ballistic transport. To realize how close to the ballistic limit a nanoFET operates, calculating the ratio of the mean-free-path to the critical length at the top of the source-to-channel barrier becomes an interesting investigation. After an introduction concerning the ballistic transport into the current devices, we will present the electrically characterized architectures and the methodology used to extract the backscattering coefficient (r(SAT)) for different gate lengths (10, 20 and 70 nm) and with temperatures ranging from 100 K to 290 K. We found that although the gate length is very small, the Double-Gate MOSFETs (DGMOSFETs) are not so close to the ballistic frontier (r(SAT) = 0). (c) 2007 Elsevier Ltd. All rights reserved.