Broadband Microwave Signal Dissipation in Nanostructured Copper Oxide at Air/Film Interface
Yaw S. Obeng, Papa K. Amoah, Christopher E. Sunday, Jesus Perez, Uros Cvelbar, Martin Kosicek
Contactless broadband microwave spectroscopic technique (a.k.a., broadband dielectric spectroscopy (BDS)) enables the accurate operando analysis of the electrical and magnetic properties applying without compromising the kinetic conditions of the experiment. The BDS method is a sensitive probe to the actual electronic structure of species and is most relevant to redox reactions involving the charge carrier reservoirs involved charge-transfer based sensors. In this paper, using BDS (from a few Hz to 40 GHz), we have studied and characterized the oxidation of a copper layer in a purposely built prototypical 3-D integrated circuit (3D-IC)) during cycled high-temperature storage. We show that the microwave signal loss in these devices is attributable to the energy dissipation through the signals interactions with the conductive and magnetic properties of the oxidation products formed around unpassivated copper features. The results demonstrate that contactless BDS may be an excellent metrology for applications that use metal oxide as sensing elements.