Compact modeling beyond device physics

Device modeling is an important research subject due to its role to bridge device theory to applications. Many models, however, are only limited to obtaining analytical solutions to some physical parameters or current-voltage equations. These models can be published but are difficult to achieve further applications. To have a model that really works in a circuit simulator, a lot of transformation is needed to achieve completeness to include not only terminal current versus voltage characteristics, but also terminal charge versus voltage characteristics. The expressions need to be continuous and differentiable from negative to positive infinity. In addition, the derivatives including trans-conductance and trans-capacitance also need to be continuous and differentiable. Smooth functions may need to be introduced to avoid abrupt transitions to help convergence. The process to convert a published model to a practical one requires a different kind of skill sets, which are well described but not perceived by most researchers. In this presentation, the process to produce a practical model beyond device physics, including some recent development to help this process will be described.