VOLTERRA INTEGRAL-EQUATION MODELS FOR SEMICONDUCTOR-DEVICES

Yan Roosbroeck's bipolar drift diffusion equations cover the qualitati ve behaviour of many semiconductor devices. The complexity of the mode l equations however prevents efficient implementations needed in circu it simulations. Under close-to-thermal-equilibrium biasing conditions (zero space charge assumption, low injection limit) the van Roosbroeck system can be replaced by a system of coupled non-linear Volterra int egral equations of the second kind. Involving only the macroscopic qua ntities current, applied voltage and serial resistance this Volterra s ystem can be handled with comparably little effort. Volterra integral equations models are formulated for a large class of semiconductor dev ices with abrupt pn-junctions. The model equations are made explicit f or diodes, transistors and thyristors, a survey on various results con cerning Volterra models describing the switching behaviour of pn-diode s is given.