Method of fabricating ruthenium-based contact plug for memory devices

Abstract

A method for fabricating semiconductor memory cells such as dynamic random access memory (DRAM) and ferroelectric random access memory (FRAM) with improved contact between the capacitor electrode and the underneath device area. It includes the following main steps of: (1) forming a first dielectric layer on a wafer surface; (2) forming at least one through opening in the first dielectric layer; (3) forming a ruthenium based plug in the through opening; and (4) forming a capacitor in contact with the ruthenium based plug. The ruthenium based plug can be made of ruthenium metal, conductive ruthenium oxide, or a stack of conductive ruthenium oxide and ruthenium metal. The method allows the memory cell to be made without the need for a barrier, which is required to protect the storage electrode from reacting with Si atoms during the fabrication process.