High frequency considerations for multi-point contact interfaces

Abstract

A statistical model based on random variations of surface features was used to estimate the resistance and capacitance of a typical multi-point contact interface. Values for clean and degraded contacts were calculated and show that, as a contact degrades, the resistance goes up and the capacitance initially rises and then falls as a film grows at the contact interface. Moreover, data were provided that show consistency with predictions from the statistical model. In addition, measurements of the skin effect on series resistance, including contact resistance, were conducted and show a power law frequency dependence of both bulk and contact resistance. While these data appear consistent with the analysis, it is believed that the measurement and analysis techniques can be improved to provide more accurate results. Moreover, the results reveal that high frequency data transmission can be affected by the impedance of a degraded contact interface. While the latter was not fully quantified, this study showed the levels where degradation may impact high frequency signal propagation. It is believed that further refinement of the techniques used in this study will help quantify high frequency effects from the impedance of a multi-point contact interface.