Large-signal time-domain modeling of avalanche diodes

Large-signal, time-domain modeling (simulation) of avalanche diodes is potentially a very accurate and useful tool for the study and design of these devices. Unfortunately, difficult computational problems of stability, accuracy, and efficiency can easily interfere with the production of meaningful, cost-effective results. This paper identifies the problems commonly encountered, including poor accuracy of the avalanche generation description; numerically induced pseudodiffusion; modeling of unsaturated velocity and negative mobility carrier dynamics; field reversal; and the treatment of the diode-load interaction, and describes numerical methods developed to overcome them. The methods described are believed to represent a current state-of-the-art efficiency/accuracy compromise for avalanche-diode simulation.