Electrical Modelling of Silicide Ohmic Contacts for MOS Devices

Multiple layer ohmic contact structures incorporating silicide materials are becoming increasingly popular in semiconductor devices. However the use of multiple layers for ohmic contacts makes the modelling and calculation of the contact resistance Rc a non-trivial problem. In this paper results from the analytical Tri-Layer Transmission Line Model (TLTLM) and a two-dimensional finite-element model are compared when both models are used to calculate parasitic resistances in the MOSFET ohmic contact and gate-drain region. From these comparisons, an improved understanding of contact behaviour and an appreciation of the limitations which apply when using the TLTLM can be obtained.