A novel all-inverter CMOS based dose control circuit for using vertically aligned carbon nanofibers in maskless lithography

This paper presents a prototype implementation of a circuit that can control charge emission from the vertically aligned carbon nanofibers (VACNF), for use in the implementation of digital electrostatic e-beam array lithography (DEAL). This lithography technique can be used to fabricate ultra-small feature size devices, while cutting down the manufacturing costs of photomasks. These VACNF´s are found to be quite robust for use as micro-fabricated field emission devices. The all inverter based dose control circuit (DCC) presented in this paper was fabricated using a standard 0.5 μm CMOS process to improve the dose-rate accuracy, when using these VACNF´s for etching in maskless lithography. Simulation and measurement results are compared and analyzed, and future work for improving the design is discussed.