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

Abstract

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.