Monolithic three-dimensional integration of carbon nanotube FET complementary logic circuits

In this paper, we experimentally demonstrate, for the first time, a scalable integration process for monolithic three-dimensional ICs (3D ICs) using carbon nanotube field-effect transistors (CNFETs). We demonstrate the flexibility of our approach using CNFETs with high I_ON/I_OFF that can be placed on arbitrary layers of monolithic 3D ICs, and connected using conventional vias to build fully-complementary monolithic 3D logic gates and monolithic 3D multi-stage logic circuits. We also demonstrate that such monolithic 3D logic gates can operate correctly over a range of supply voltages from 3V to 0.2V.