Optimization of a SiCl4-Ar inductively coupled plasma etching process for InP-based waveguide devices

SiCl₄ exhibits the advantages of low etching damage and high etching anisotropy, and provides a robust foundation for the fabrication of high-quality InP-based waveguide devices. This study investigates the etching performance of SiCl₄/Ar mixed gases on InP-based waveguides during the inductively coupled plasma (ICP) etching process. Particular emphasis is placed on analyzing the effects of physical bombardment, chemical reactions, and chamber pressure on the morphology of the waveguides. Through systematic optimization of the etching process parameters, waveguides with high etching anisotropy, continuous smooth and vertical sidewalls, and an etching profile free of micro-trenches were successfully fabricated.