Precision etching for multi-level AlGaAs waveguides

We present inductively-coupled-plasma, reactive-ion-etching (ICP-RIE) techniques with 2 orders of magnitude difference in etch rates, for the AlxGa1-xAs material system. These precise etching processes are used to produce waveguides in a multi-guide vertical integration (MGVI) AlxGa1-xAs chip. The MGVI AlxGa1-xAs chip vertically integrates multiple guiding layers that usually have different material properties. The fabrication of these chips requires precise and anisotropic etching. The first etching recipe used BCl3 and achieved an etch rate of 0.25 nm/s while the second one used Cl-2/N-2 gases and achieved an etch rate of more than 20 nm/s. Simple AlxGa1-xAs nanowaveguides of 800 nm width were fabricated using these recipes. We measured a propagation loss of 6.7 dB/cm at the wavelength of 850 nm. (C) 2017 Optical Society of America