In this study we present the results of electroless deposition of silver (Ag) and silver tungsten [Ag(W)] layers on Si, intended for application in microelectronics and microelectromechanical systems (MEMS) technology. Silver has excellent resistivity but its thin-film properties and its vulnerability to corrosion may cause a problem. In this work we present a novel Ag(W) type of layer that has improved thin-film properties, such as resistivity and surface roughness, and can serve as both barrier layer and capping layer for corrosion protection of the Ag thin films. The thin-film composition was studied as a function of the deposition parameters. We found the presence of tungsten, up to 3.1 atom %, and oxygen, up to 8 atom %, in addition to the silver atoms. We also studied the thin-film morphology using atomic force microscopy and scanning tunneling microscopy imaging of the surface after each process step. Finally, we discuss the possible mechanisms for the deposition of Ag(W). (C) 2000 The Electrochemical Society. S0013-4651(00)01-043-0. All rights reserved.
