Theoretical Study of Self-Heating-Induced Thermal Stress Effects on Quantum Transport in p-Type Ultrathin Body-FinFET by Multiphysics Simulation

Self-heating of the device will intensify the thermo-mechanical effects, leading to an increase in thermal stress. Currently, most of the research focuses on strain engineering of the device by intentionally introducing mechanical stress. However, how thermal stress affects the performance of nanoscale transistors remains unclear. Thus, in this manuscript, a comprehensive coupled Multiphysics simulation is performed to investigate the self-heating induced thermal stress effects on quantum transport in the p-type ultrathin body (UTB)-FinFET. The quantum transport equation with consideration of thermal stress effects by the strain term in
${k}\cdot {p}$
Hamiltonian, heat conduction equation, and equilibrium equations of solid mechanics are solved self-consistently. Then, the impacts of self-heating-induced thermal stress on hole effective mass, hole average velocity, and current density of the FinFETs with different crystal orientation configurations and channel lengths are compared and analyzed. The simulation results show that thermal stress can decrease or increase the ON-state current depending on the crystal orientation configuration. Further analysis of the band structure obtained from the Hamiltonian shows that thermal stress can change the material properties such as the hole effective mass of the top subband, thus leading to the variations of device characteristics.