Seamless Feedthroughs for Neurotechnologies Using Diffusion Processes

Abstract

Electrical feedthroughs are a major part of active implantable medical devices. They are responsible for connecting the implants’ active sites with the processing electronics that are usually hermetically packaged. They deliver conductive pathways through the package wall and have to avoid premature device failure due to ingressing humidity. With decreasing device size, the requirements on the single parts increase, including the electrical feedthroughs. As conventional electrical feedthroughs rely on opening the hermetic bulk material of the package that introduce leak paths, they always raise the potential that water enters the package inside alongside these interfaces. Therefore, a proof‐of‐concept study of a new hermetic electrical feedthrough design that leaves the hermetic bulk material, that is, silicon, intact is presented. The concept is based on diffusing noble metals, Pt and Au, into the semiconductor bulk, resulting in a quasi‐localized resistance increase of the silicon. It is shown that by variation of diffusion temperature, time, the substrate cooling, and others, a parameter combination is found with which optoelectronic components can be driven through an intact silicon substrate.