SURFACE PRECIPITATES ON SINGLE-CRYSTAL LINBO3 AFTER DRY-ETCHING BY CHF3 PLASMA

The CHF3 electron cyclotron resonance (ECR) plasma etched LiNbO3 (LN) surface was analyzed chemically and crystallographically to investigat e the dry-etch machining process for LN crystal, which was recently ne eded to obtain broader-band optical modulators. The etched surface was entirely covered with amorphous-like precipitates having similar to 7 0 nm diameter. These precipitates (or a part of them) were thought to be LiF from Auger electron and x-ray photoelectron spectroscopy. The r esults indicated that the LiF was formed and remained on the etched su rface while the Nb was almost completely removed.