Low damage atomic layer etching of ZrO2 by using BCl3 gas and ar neutral beam.

This study examined the etch characteristics of ZrO2 etched using an atomic layer etching (ALET) system with BCl3 gas for adsorption and an Ar neutral beam for desorption. The effect of the BCl3 gas pressure and Ar neutral beam dose on the etch characteristics was examined. The results showed that the ZrO2 etch rate was maintained at a constant etch rate of 1.07 angstroms/cycle at a BCl3 gas pressure > 0.15 mTorr and an Ar beam flux > 1.485 x 1016 atoms/cm2 x cycle. Under these constant etch rate conditions, the surface roughness of the etched ZrO2 was similar to that of the as-received ZrO2. The surface composition of ZrO2 etched by ALET was compared with that etched by BCl3 inductively coupled plasma (ICP). The surface composition of ZrO2 etched by ALET showed a similar composition to that of the as-received ZrO2 while that etched by BCl3 ICP showed a Zr-rich surface.