Effect of gas mixing ratio on MgO etch behaviour in inductively coupled BCl3/Ar plasma

The etching behaviour of MgO thin films in BCl3/Ar plasma was investigated. It was found that the increasing Ar mixing ratio under the constant total pressure conditions causes the monotonic decrease of MgO etch rate, which falls from 93 to 17 nm/min. Plasma diagnostics combined with a 0-dimensional plasma model showed the noticeable sensitivity of both electron temperature and electron density to the process parameters as well as monotonic changes of both densities and fluxes of active species. The analysis of etching kinetics and mechanisms was performed. The results showed in the BCl3-rich plasma the etching process is dominantly supplied by the chemical pathway through the ion-assisted chemical reaction.