On the Formulation of Self-Heating Models for Circuit Simulation

Different approaches to implement self-heating effects in a compact model are evaluated. The traditional approach using a subcircuit with the addition of an internal node can lead to significant increase in the simulation time. In contrast, by directly solving self-heating equations, the internal node is eliminated in the circuit Jacobian matrix. The resulting simulation time can be shortened in principle up to 60% or more without sacrificing the accuracy. The accuracy and time for self-heating simulations formulated using different approaches are compared in this paper to study their tradeoff. In addition, a generic approach to eliminate the need for internal nodes is proposed and demonstrated using the non-quasi-static effect model.