ICP etching of sapphire substrates

The etching behavior of sapphire has been investigated in an inductively couple plasma using Cl₂, BCl₃ and CH₂Cl ₂ as the reagent in this study. Inductively couple plasma etching rate of sapphire was investigated as function of a mixing gases ratio. The highest sapphire-etching rate was archived (1000 Å/min) with mixing BCl₃/Cl₂ gases for a coil power of 600 W, r.f. power of 150 W and process pressure of 5m Torr. The scanning electron microscopy was used to investigate the surface morphology and sidewall of sapphire. Several etching conditions yield highly anisotropic profiles with roughness sidewalls. These results have direct application to the fabrication of patterned sapphire substrate, which reduce the threading dislocation and increase the output light power and lifetime.