Using a Device State Library to Boost the Performance of TCAD Mixed-Mode Simulation

Abstract

Technology computer-aided design (TCAD) device and small circuit simulations use numerical and physics models to investigate the properties and performance of circuits before they undergo fabrication. Thus, these simulations play a significant role in VLSI design, optimization, and verification. However, they suffer from poor convergence and high CPU times, especially when performing TCAD mixed-mode simulations. In this paper, we propose a new simulation flow to address this challenge. We use device states captured from single devices to build a device state library. Then, we leverage device-level solutions to form a global initial guess for circuit-level simulations that are based on the full Newton algorithm. This leads to a significant efficiency enhancement. The average speedup for quasi-stationary (or dc) operating point establishment for a standard cell library and a mirror adder is $6.9\times$ and $21.2\times$ , respectively, whereas the CPU time for static random access memory static noise margin extraction is reduced by 47.0%.