The Analysis of Multiwall Carbon Nanotubes as Through Silicon Via by Equivalent Circuit Model at Different Operating Temperatures in Multilayers Stacking Scheme

In nowadays 3-D integrated circuits (3DICs) technology, through silicon via (TSV) is the most important component, which connects homogeneous or heterogeneous dies vertically with each other. Based on our previous research, carbon nanotubes (CNTs) have been considered as TSV filling materials due to their outstanding mechanical and electrical properties. However, the operating temperatures would significantly affect the performance of signal transmission in CNT TSV. To evaluate the electrical characteristics of CNT TSV with different realistic temperatures, the considerations of temperature-dependent electron mean free path (MFP, $\lambda$ ), and number of conducting channels of CNTs are necessary. In this work, the equivalent circuit model of CNTs as TSV is presented and the simulated electrical behaviors are benchmarked with other literatures. Based on our proposed model, multiwall (MW) CNTs' electrical performance in multilayers stacking system under different operating temperatures is investigated. In addition, we also compare the electrical performance of CNTs as TSV with the conventional filling material (Cu). It shows that CNT TSV has more advantages than Cu TSV when the operating temperature becomes higher. In summary, the proposed equivalent circuit model in this work is more comprehensive and yields more realistic results. Meanwhile, CNT is a promising material for TSV under varying operation temperatures.