MOS TRANSISTOR AND METHOD FOR FORMATION OF CONDUCTIVE DIFFUSED BARRIER ON INTERFACE BETWEEN ITS METAL LAYER AND SILICON LAYER

摘要

PURPOSE: To enable a conductive diffusion barrier at an interface to be kept excellent in state even if a metal contact is exposed to high temperatures by a method wherein metal is deposited and exposed to plasma mainly composed of nitrogen so as to generate a silicon nitride layer at an interface, and then annealing is carried in an inert atmosphere so as to remove nitrogen. CONSTITUTION: Metal which forms an interface is selectively deposited, and then a conductive diffusion barrier is formed on an interface between a metal layer and a silicon layer in an integrated circuit. In this case, the interface is exposed to plasma of mainly composed of nitrogen at least for five minutes to be heated up to a temperature of 500 deg.C or above so as to generate a silicon nitride layer which serves as a diffusion barrier. Then, a composite layer composed of the interface and the diffusion barrier is subjected to annealing in an inert atmosphere to remove nitrogen introduced into the metal layer in a preceding process. For instance, the interface is exposed to nitrogen plasma at least ten minutes to be heated up to at least a temperature of 700 deg.C so as to form a silicon nitride layer of thickness 2 nm or so to serve as a diffusion barrier.