Enhancement of the etch rate of $LiNbO3$ by prior bombardment with MeV $O2+$ ions

The implantation of $LiNbO3$ with 5 MeV $O2+$ ions has been examined as a means of increasing the rate of subsequent reactive ion etching in $CF4/CHF3$ plasmas. The etch rate of $LiNbO3$ implanted at a dose sufficient to amorphize the substrate $(1×1015–5×1015$ ions $cm−2)$ was ⩽3 times higher than in unimplanted substrates. The measured etch rates in $CF4/CHF3$ plasmas were essentially independent of the implant dose below $3×1014$ ions $cm−2$ but increased significantly at and above $1×1015$ ions $cm−2.$ This transition was correlated with the onset of amorphization. In an Ar plasma, the etch rate of $LiNbO3$ was unaffected by prior million electron volt implantation and was an order of magnitude lower than in the $CF4/CHF3$ plasmas. These results have suggested that the damage induced by million electron volt implantation acted to accelerate the process of ion-enhanced chemical etching in $LiNbO3$ but had no significant influence on the process of physical sputtering in an Ar plasma.