Quasiatomic layer etching of silicon nitride enhanced by low temperature

Plasma atomic layer etching is a dry process using dose step to modify material’s surface chemistry and an etch remove the modified layer. This method of has certain advantages over reactive ion due its self-limiting for highly controllable depth reduced roughness. In this paper, we expand upon anisotropic, plasma recipe used thin films silicon nitride, which uses H2 material SF6 surface. Several modifications are made recipe, including reduction in pressure during from 500 20 mT, allow compatibility with modern inductively coupled plasma-reactive systems. We then explore at low wafer temperature find spontaneous isotropic etching. results enhancement aspect process, improvement etched sidewall homogeneity, decrease roughness, potential be useful reducing optical loss nitride waveguides other nanoscale devices nitride.