In this paper, we examine mechanisms of electron transport across the metal-carbon nanotube (CNT) interface for two different types of multiwall carbon nanotube (MWNT) architectures, horizontal or side-contacted MWNTs and vertical or end-contacted MWNTs. Horizontally aligned nanotube growth and electrical characteristics are examined with respect to their potential applications in silicon-based technologies. Recent advances in the synthesis techniques of vertical MWNTs have also enhanced the possibility for a manufacturable solution incorporating this novel material as on-chip interconnects or vias as copper interconnect feature sizes are scaled into the sub-100-nm regime. A vertical MWNT architecture is presented that may be suitable for integration into silicon-based technologies. The growth method for this architecture and its effect on electrical characteristics are examined. Through simulations, dc measurements, and comparison of our results with previous studies, we explain why high contact resistance is observed in metal-CNT-metal systems.