Optimisation of metal connections in lateral DMOS transistors for driving applications

This paper presents the optimisation of the routing of multi-finger current drivers, based on lateral DMOS transistors, for switching applications, in order to limit the metal contribution. to the total driver on-resistance. The metal2 collecting current from the device fingers out of the source and drain, is shown to be the major contributor to the added series resistance for all aspect ratios, as long as the number of metal2 tracks is large enough. The experimental characterisation of the metal connection influence on the device on-resistance is successfully supported by circuit simulations, based on a lumped resistor network model of the driver.