Computational Study of Thermal Stress in Gate-All-Around Nanosheet Field Effect Transistor

The gate-all-around nanosheet field effect transistor (GAA-NSFET) is an alternative for sub-7nm CMOS technology nodes. Its 3D stacked structure offers a good solution to short-channel-effects and leads to high integration density, and results in high power consumption per unit volume and more serve self-heating effect in GAA-NSFET. The more temperature rise caused by the severe self-heating effect introduces strong thermal-mechanical coupling effect and affects the performance and reliability of transistors. In this paper, we use the finite element method to simulate the thermal-mechanical coupling processes in GAA-NSFET. The heat conduction equation is solved numerically to get the temperature distribution. The kinetic equation is then solved to get the displacement distribution and thermal stress. The simulation results show that the hot spot of the transistor is in the channel, and the greatest thermal stress occurs in the channel region as well.