Selective etching in LiNbO3 combined of MeV O and Si ion implantation with wet-etch technique

The selected etching in lithium niobate (LiNbO3) crystals is carried out by two different ion implantation and differential wet etching. The LiNbO3 samples are cleaned and partially masked with photoresist in lithographic procedure firstly, followed by 1.5 MeV O+ or Si+ ion implantation at a dose of 1×1015 ions/cm2 at room temperature. It is found that the ion implanted region can be etched more easily than that protected by photoresist mask using mixture of hydrofluoric and nitric acids at room temperature. The surface morphology of the etched samples is examined using surface profilometer and SEM. Ridge structures are formed by the ion implantation and the subsequent selective wet etching. The results show that this technique may be suitable for fabrication of high quality ridge waveguides.