Fabrication and electrical characteristics of carbon nanotube-based microcathodes for use in a parallel electron-beam lithography system

Abstract

This article presents an overview of the “Nanolith” parallel electron-beam (e-beam) lithography approach. The e-beam writing head consists of an array of microguns independently driven by an active matrix complementary metal–oxide–semiconductor circuit. At the heart of each microgun is a field-emission microcathode comprised of an extraction gate and vertical carbon nanotube emitter, whose mutual alignment is critical in order to achieve highly focused electron beams. Thus, in this work, a single-mask, self-aligned technique is developed to pattern the extraction gate, insulator, and nanotubes in the microcathode. The microcathode examined here (150×150 gates, 2 μm gate diameter, with multiple nanotubes per gate) exhibited a peak current of 10.5 μA at 48 V when operated with a duty cycle of 0.5%. The self-aligned process was extended to demonstrate the fabrication of single nanotube-based microcathodes with submicron gates.