Role of mechanical stress on the electrothermal and OFF state current in scaled FinFET devices

The electrothermal characteristics and leakage current of a tall FinFET device were investigated using the hydrodynamic transport model coupled with a quantum-corrected diffusive transport mechanism-based TCAD simulation. The effects of strain on the electrothermal characteristics and the gate-induced drain leakage (GIDL) due to source/drain doping with carbon and germanium in n-/p-FinFETs, respectively, are explored. The carbon mole fractions were varied from 0 to 0.1 in the Si_1-xC_x doped source/drain region to induce local strain in the channel region. The intrusion of the dopants in the source/drain region improves I_D by 50.79%, but it increases GIDL current by two orders. The strain causes a reduction in the effective mass of electrons due to band deformation. As a result, most high-energy electrons lose their kinetic energy to the lattice, elevating the lattice temperature of n-FinFET to 363 K. Consequently, nearly 11% degradation in I_D is observed in the n-FinFET due to the self-heating effects. A similar effect is observed in the p-FinFET, where the lattice temperature increases to 357 K at 90% germanium concentrations. Furthermore, the presence of a non-uniform electric field creates local quantum confinement of charge carriers in the channel, altering the band gap and intensifying the GIDL component in the n-/p-FinFET.