Impact Ionization Behavior in Bulk Fin Field Effect Transistors with Fin Body Width and Bias Conditions

Abstract

The impact ionization behavior of bulk fin field effect transistors (FinFETs) was investigated with respect to fin body width (Wfin) and bias conditions. As fin width decreases to less than about 50 nm, the effect of parasitic source/drain series resistance becomes significant, resulting in a decrease in the impact ionization rate due to the increasing voltage drop across the resistance. We analyzed the ISUB/ID trend depending on the bias conditions (VGS=VDS and VGS=VDS/2) for devices with a Wfin thicker than 50 nm. Through two-dimensional device simulation, we showed the voltage drop and the peak electron temperature for various Wfin. It was also shown that the contact resistivity between the source/drain and the metal electrode is very important in the bulk FinFET with a very thin fin width.