Surface Evaluation of LiNbO3, LiTaO3 Crystals Etched Using Fluorine System Gas Plasma RIE

Abstract

Etching characteristic LiNbO3 and LiTaO3 single crystals has been investigated using plasma RIE with mixture gases of CF4/Ar, CF4/H2, CF4/Ar/H2. The etched surface was evaluated by means of atomic force microscopy and X-ray diffraction methods. The in situ surface temperature of the sample during RIE was measuresd. F atoms exist in the contamination layer, such as sediments, on the surface etched using the mixture gases of CF4, Ar and H2 gases. The etch rate was dependent on the orientation of a crystal. The etch rate of LiTaO3 was less than that of LiNbO3.