Ferro-Electrically Enhanced Proximity Communication. Open Access

Capacitively-coupled communication between chips, commonly known as PxC, represents a new class of I-O signaling that offers substantially improved off-chip bandwidth density. However, this form of communication presents a challenge from a packaging perspective, since tight chip alignment tolerances are required to maintain high signal fidelity and avoid cross coupling between neighboring channels. To mitigate the packaging constraints, capacitive coupling between the communication pads can be enhanced with materials that have high dielectric coefficients. Here, ferroelectrics hold promise over contemporary low- and high-k dielectrics, however their processing conditions need to be better understood and the compatibility with CMOS circuitry has to be established during integration with a back end of the line process module. In this paper we present experimental results on microfabrication modules for various families of ferroelectrics when monolithically deposited on Silicon. Additionally, we report their associated dielectric properties as extracted by measured capacitance enhancements in our fabricated devices. In this work Strontium Titanate and Barium Strontium Titanate films are sputter deposited on platinum atop Silicon. Capacitive measurements were accomplished by microfabricating electrodes atop these structures in geometries that are size and shape dependant. Dielectric coefficients as high as 400 times that of air are measured.