The application of macroporous silicon to silicon bulk micromachining generally requires forming macropores locally on a silicon substrate according to a predefined pattern. In this work, several mask schemes, including photoresist, metal, silicon nitride (Si3N4), silicon carbide (SiC) and silicon nitride/silicon dioxide (Si3N 4/SiO2, are investigated for local formation of macropores in n-type silicon substrates. It is shown that overetching at the edge of the pattern is a challenging issue, which prevents a precise control of the etched areas. The cause of the issue and possible solutions are associated with the quality of mask films, the mechanical and electrical properties of the interface between the mask and the substrate and the distribution of carriers across the patterned area.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Mechanics of Materials
- Mechanical Engineering
- Electrical and Electronic Engineering