Recent advances in semiconductor technology offer vertical interconnect access (via) that extend through silicon, popularly known as through silicon via (TSV). This book provides a comprehensive review of the theory behind TSVs while covering most recent advancements in materials, models and designs. Furthermore, depending on the geometry and physical configurations, different electrical equivalent models for Cu, carbon nanotube (CNT) and graphene nanoribbon (GNR) based TSVs are presented. Based on the electrical equivalent models the performance comparison among the Cu, CNT and GNR based TSVs are also discussed.