New tools for the direct characterisation of FinFETS

Abstract

This chapter discusses how classical transport theories such as the thermionic emission (Sze, 1981), can be used as a powerful tool for the study and the understanding of themost complexmechanisms of transport in fin field effect transistors (FinFETs). Bymeans of simple current and differential conductance measurements, taken at differ- ent temperatures and different gate voltages (VG ’s), it is possible to extrapolate the evolution of two important parameters such as the spatial region of transport and the height of thermionic barrier at the centre of the channel. Furthermore, if the measurements are used in conjunction with simulated data, it becomes possible to also extract the interface trap density of these objects. These are important results, also because these parameters are extracted directly on state-of-the-art devices and not in specially designed test structures. The possible characterization of the different regimes of transport that can arise in these ultra-scaled devices having a doped or an undoped channel are also discussed. Examples of these regimes are full body inversion and weak body inversion. Specific cases demonstrating the strength of the thermionic tool are discussed in Sections 10.2, 10.3, and 10.4.