Wafer-scale fabrication of a vertically-aligned NEMS switch based on carbon nanofibers

Fabrication of nanoscaled transistors based on carbon nanotubes and inorganic nanowires is typically demonstrated with a “pick-and-place” or similar method which allows for fabrication of small numbers of transistors at a time. While these, and other, devices have been used to demonstrate potential applications of carbon nanotubes, these methods are not applicable to wafer scale production with large yield. Carbon nanofibers (CNFs) show great promise as potential mechanical elements in nanoelectromechanical system (NEMS) devices while their vertical orientation allows for integration into standard vias or other devices with an inherently low footprint. Here, we discuss a CMOS compatible wafer-scale fabrication scheme for scalable production of carbon nanofiber based NEMS switch devices. Well dimensions are defined by standard photolithography approaches and e-beam lithography is utilized for CNF catalyst definition. A multi-stack trench etch is used to define wells in which CNFs are grown using the commonly employed PECVD method. Integration issues related to multi-layer etch and CNF growth conditions are also presented. This approach demonstrates promise for integration of a low-footprint, high-performance NEMS device into a CMOS process flow.