General aspects of barrier layers for very-large-scale integration applications I: Concepts

Abstract

Barrier layers are frequently used for improving the reliability of integrated circuits by reducing the material reaction in a multilayered device structure. To meet the size-scaling requirement in very-large-scale integration (VLSI), effective barrier layers become increasingly important. In this paper the general requirements of barrier layers are first described in view of the future device miniaturization. Then the function of the barrier layer in reducing the mass transport is discussed by considering separately the nature of the diffusivity and the driving force. This leads to two possibilities of establishing barrier layers: a reduction in the diffusivity or a reduction in the driving force. On this basis, three types of barrier layers can be conceived, namely the diffusion barrier, the reaction barrier and the driving force barrier. The function and method for establishing these barriers are described and illustrated by some known applications, several of which are pertinent to VLSI technology. Finally, the effectiveness and limitation of these methods are assessed. © 1982.