Analytical Thermal Model for Self-Heating in Advanced FinFET Devices With Implications for Design and Reliability

A rigorous analytical thermal model has been formulated for the analysis of self-heating effects in FinFETs, under both steady-state and transient stress conditions. 3-D self-consistent electrothermal simulations, tuned with experimentally measured electrical characteristics, were used to understand the nature of self-heating in FinFETs and calibrate the proposed model. The accuracy of the model has been demonstrated for a wide range of multifin devices by comparing it against finite element simulations. The model has been applied to carry out a detailed sensitivity analysis of self-heating with respect to various FinFET parameters and structures, which are critical for improving circuit performance and electrical overstress/electrostatic discharge (ESD) reliability. The transient model has been used to estimate the thermal time constants of these devices and predict the sensitivity of power-to-failure to various device parameters, for both long and short pulse ESD situations. Suitable modifications to the model are also proposed for evaluating the thermal characteristics of production level FinFET (or Tri-gate FET) structures involving metal-gates, body-tied bulk FinFETs, and trench contacts.