Formation of Silver Sulfide Layers and their Influence on the Electrical Characteristics of Contacts in the Field of Information Technology

摘要

The use of silver as a contact material in the field of information technology is often limited because of the formation of insulating Ag_2S layers that occurs in a sulfuric atmosphere. This paper analyzes the growth of silver sulfide layers on three different silver surfaces, produced by casting, electroplating and physical vapor deposition, applying different sets of corrosion parameters. The second part contains an evaluation of these corroded Ag surfaces with regard to the characteristics which are relevant in practice, such as thickness, hardness, fritting voltage and contact resistance. No difference in contact performance were detectable with contact forces exceeding 8 cN. At lower contact and after severe corrosion conditions the casted Ag probe seems to have substantial advantages in comparison to sputtered layers, while electroplated silver shows intermediate behavior.