Micro and Nanofabrication: Chemical Reactions and Etching Processes

This lecture covers the chemical reactions involved in micro and nanofabrication processes, focusing on Si etching in acidic media. It explains the overall reactions, the role of oxidants, and the generation of SiO₂. Additionally, it discusses the ternary diagram for the HNA bath, iso-etch curves, and the anisotropic etching profiles in alkaline baths. The lecture also explores the etching of Si with boron, the origin of etching anisotropy, and the isotropic etching of p-doped and n-doped Si with electrical bias. It concludes with the formation of porous n-type Si and macropores in Si under high anodic voltage. The content is illustrated with diagrams and examples.