Boltzmann-Statistics-Aware Non-Quasi-Static-Charge Model for IC Simulations

In this article, Boltzmann statistics consideration is added to the charge-deficit large-signal non-quasi-static (NQS) model. The new model eliminates the nonphysical negative drain transport (as opposed to displacement) current at large drain voltage and under fast gate voltage (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text {V}_{\text {gs}}$ </tex-math></inline-formula>) turn-on. The new model agrees well with the technology computer-aided design (TCAD) simulation data for turn-on and turnoff transients and for all the drain voltage (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text {V}_{\text {ds}}$ </tex-math></inline-formula>) values, small or large. In addition, the model captures the temperature dependence of channel charge partition between source charge and drain charge in agreement with TCAD simulation results, thus reconfirming the importance of including Boltzmann statistics in NQS models. The new Boltzmann-aware NQS model is implemented in Verilog-A and tested using commercial circuit simulators. It is intended for the simulation of large-signal and small-signal NQS, and high-speed analog, logic and memory circuits.