Fabrication of Silicon Microtips with Integrated Electrodes

Abstract

This paper describes a simple method to fabricate silicon microtips with integrated self-aligned polarization electrodes for development of MEMS and electron field emission devices. The method is based on the wet bulk micromachining of the silicon substrate in KOH solutions and utilizes low stress PECVD SiOxNy films obtained at low temperatures (320°C) as structural material for both mechanical support and electrical insulation of the electrodes. For the electrodes sputtered Cr films were utilized. The microtip formation process was studied by optical and electronic microscopy to analyze tip geometry and the characteristic etch rate of the different stages during the tips formation. The fabricated devices were matrixes with different numbers of microtips, each with a typical height of 52 μm and with diameter at the apex below 1 μm. In the best case, the distance between the apex of the tips and the metallic electrode was lower than 5 μm. The results also show that the low stress SiOxNy film is essential to attain the necessary flatness required by the process.

A Cellular Automata Based Multi-Process Microfabrication Simulator

“…Assuming the spacing between layers of the (001) plane to be 0.5 µm so as to have the cross arms with a width of 50µm, the resulting microtip will have a height of 64 µm. This is slightly larger than the experimental results of 52 µm [7].…”