High‐Precision Transient Electrothermal Co‐Simulation Framework: Coupling of <scp>BSIM</scp> ‐ <scp>CMG</scp> and High‐Order Thermal Network

ABSTRACT Aggressively scaled devices with high power density wrapped around the low thermal conductivity material in narrow space are susceptible to severe self‐heating effect (SHE), especially gate‐all‐around FETs (GAAFETs). Conventional BSIM‐CMG compact model—relying on first‐order thermal RC networks—severely underestimates high‐frequency transient SHE impacts. In this paper, a transient electrothermal co‐simulation framework coupled BSIM‐CMG with a high‐order thermal RC network is developed to accurately capture self‐heated temperature prediction. Self‐heating temperature rise is calculated through a high‐order thermal network in which each RC component represents a discrete thermal dissipation path corresponding to one specific thermal region. The high‐order thermal network substitution is accomplished via an HDL module that redefines power generation and dissipation computations at each thermal node, followed by the integration into the BSIM‐CMG model for enabling comprehensive and precise transient thermal evaluation in device‐circuit level. In contrast to the conventional methods, the proposed framework can more effectively replicate the phenomenon of multiple thermal time constants present in transient temperature responses of GAAFETs. Its simulation results exhibit better consistency with the TCAD, with an error of less than 2% at a given frequency of 200 MHz. Moreover, the proposed framework is further validated by the electrothermal co‐simulation of ring oscillators and differential amplifier.