Fabrication of gated cathode structures using an in situ grown vertically aligned carbon nanofiber as a field emission element

Vertically aligned carbon nanofibers (VACNFs) are extremely promising catho de materials for microfabricated field emission devices, due to their low t hreshold field to initiate electron emission, inherent stability, and rugge dness, and relative ease of fabrication at moderate growth temperatures. We report on a process for fabricating gated cathode structures that uses a s ingle in situ grown carbon nanofiber as a field emission element. The elect rostatic gating structure was fabricated using a combination of traditional micro- and nanofabrication techniques. High-resolution electron beam litho graphy was used to define the first layer of features consisting of catalys t sites for VACNF growth and alignment marks for subsequent photolithograph y steps. Following metallization of these features, plasma enhanced chemica l vapor deposition (PECVD) was used to deposit a 1-mum-thick interlayer die lectric. Photolithography was then used to expose the gate electrode patter n consisting of 1 mum apertures aligned to the buried catalyst sites. After metallizing the electrode pattern the structures were reactive ion etched until the buried catalyst sites were released. To complete the devices, a n ovel PECVD process using a de acetylene/ammonia/helium plasma was used to g row single VACNFs inside the electrostatic gating structures. The issues as sociated with the fabrication of these devices are discussed along with the ir potential applications. (C) 2001 American Vacuum Society.