Large‐Area Rolled‐Up Nanomembrane Capacitor Arrays for Electrostatic Energy Storage

The fabrication, characterization, and optimization of large area rolled‐up ultracompact nanomembrane‐based capacitor arrays is demonstrated by combining bottom‐up and top‐down fabrication methods. The scalability of the process is tested on a 4‐inch wafer platform where 1600 devices are manufactured in parallel. By using a hybrid dielectric layer consisting of HfO₂ and TiO₂ incorporated into an Al₂O₃ matrix, rolled‐up ultracompact capacitors can have their capacitance per footprint area increased by over two orders of magnitude. Their electrical properties can be precisely controlled by adjusting the oxide composition. Furthermore, the rolling of large‐area nanomembrane‐based structures naturally results in a substantial decrease of the occupied footprint area. Such electrostatic rolled‐up ultracompact energy‐storage elements have a large potential in powering various autonomous microsystems.