Multipole rf switch contact resistance interference, an industrial application of surface analysis

Low contact resistance is vital in communication and switching systems where the insertion loss and the rf / microwave performances of multi-contact switches are pushed to maximum performance. Increased resistance in the switch contact interface is a concern for optimal operation upon first turn-on of the switch. The study of high contact resistance invited the application of the surface analysis tools XPS, SEM and EDX. Environmentally compatible cleaning of the contact parts must retain acceptable compliance with the operational requirements. Hence, the effects of various cleaning agents became a concern. Gold plated beryllium copper contact surfaces function well with the application of a synthetic oil for corrosion protection. The surface contaminants' spectra from a high resistance contact in comparison with control samples demonstrated the utility of these analytical tools. The knowledge of the relative amounts of the contaminants and the circumstances of their arrival assist in revising manufacturing processes to insure long term low resistance operation of the switch.