Silver Precipitation in Energy-Scavenging Aluminum Nitride Resonators

F.S. Alleyne, M. Ford, R. Gronsky, T.-T. Yen, A.P. Pisano
University of California, Berkeley, US

Keywords: aluminum nitride, resonators, ion implantation, MEMS, ceramics

Summary:

Despite more than a decade of experience in manufacturing of nanoelectromechanical systems (NEMS) incorporating piezoelectric elements, modern devices are still plagued by delamination at the electrode/piezoelectric interface. Consequently the electric field essential to generate and sustain the piezoelectric response of such devices is lost, resulting in device failure. Working on the hypothesis that buried conducting layers can both mitigate the delamination problem and generate sufficient electric field to engage the operation of resonator devices, we have undertaken a study of silver ion implantation to experimentally assess its feasibility. Our experiments were designed to exceed the local solid solubility of Ag in the AlN host matrix, resulting in the precipitation of Ag particles with highest concentration at the projected range of the implanted metallic ions. The objective of this study is to understand the resulting phase transformation behavior during Ag precipitation with the intent to ultimately control the electrical operation of AlN piezoelectric resonators in energy scavenging devices. Our results indicate that the Ag implanted region does indeed have potential as a buried contact layer for piezoelectric activation and sensing.