Inductively coupled plasma etching of ultra-shallow Si3N4 nanostructures using SF6/C4F8 chemistry
A single step ICP process for ultra-shallow etching of Si3N4 is proposed. Passivation (C4F8) and etching (SF6) gases are mixed to minimize etch rates. The effects of etching parameters on etch rate and surface roughness are investigated. When passivation gets too dominant, the surface roughness increases. A limited slow etch rate of 6nm/min is obtained without increasing surface roughness.
plasma etching nanostructures sf6/c4f8 icp surface roughness silicon nitride