Current conduction and reliability implications under currentramping stress of VLSI contacts

The current conduction mechanisms of VLSI contact structures have been studied using the current ramping stress method and two-dimensional device simulations. Because of Joule heating effect and the subsequent emergence of intrinsic carriers in the connecting diffusion region, reduction in electrical resistance is observed as the current ramps beyond a transition point. The transition temperature, experimentally determined I-V curve and current spread-out across the diffusion/well junction are confirmed by two-dimensional device simulations. The reliability implications and current-carrying capability of the contact/diffusion structure for VLSI applications are also discussed