Ion beam etching of barium titanate for integrated photonics

The perovskite material barium titanate (BTO) has shown great promise in the next generation electro-optical modulators integrated on Si photonic platforms. In this work, the dry etching of BTO using an argon (Ar) ion beam etching system and the underlying mechanisms are investigated. The results indicate that reducing the pressure and increasing ion beam current, ion energy, and incidence angle all contribute to an increased etch rate. The increase in ion energy and beam current leads to higher surface roughness, whereas a negative incidence angle effectively reduces surface roughness. Through the optimization of various process parameters, an etching recipe showing an etch rate of 16.1 nm/min and a postetching surface roughness of 0.486 nm is realized.