Electrical Characterization of Coaxial Silicon-Insulator-Silicon Through-Silicon Vias: Theoretical Analysis and Experiments

Coaxial through-silicon via (TSV) provides an effective solution to achieve impedance matching, reduce transmission loss, and suppress interference or noise coupling in 3-D/2.5-D heterointegrated systems. This paper presents a fabrication friendly coaxial TSV configuration based on heavily doped silicon-insulator-silicon (SIS) structure, whose electrical characteristics are studied through deriving analytical solution, performing numerical simulation, and conducting experimental measurement. The distributed resistance-inductance-capacitance-conductance (RLCG) parameters are calculated from electromagnetic theory and semiconductor physics. Wideband S-parameters of the fabricated devices are obtained using on-wafer measurement with deembedding technique, and then compared against 3-D full-wave simulations and analytical solutions, exhibiting good agreement up to 50 GHz. Results show that the proposed coaxial SIS TSV offers flexible impedance control, good matching, and low insertion loss, and supports 30-Gbps data transmission with the simpler structure as well as the lower fabrication cost compared with various coaxial TSV structures reported to date.