Barrier layers: Principles and applications in microelectronics

Abstract

The miniaturization of integrated circuit devices requires complex multilevel structures for the fabrication of their electrical contacts. Aluminum is the standard metal used in silicon device technology for low resistance interconnections. However, the low temperature reaction of aluminum with silicon makes aluminium contacts incompatible with shallow junction device processing. Therefore, a barrier layer is needed between the two. The basic function of the barrier layer is to prevent aluminum–silicon intermixing by reducing the mass transport. The realization of this property is discussed from a materials point of view. Various barrier materials are surveyed and compared to the requirements for microelectronics device applications.