DIRECTIONAL REACTIVE-ION-ETCHING OF INP WITH CL-2 CONTAINING GASES

Reactive ion etching (RIE) of InP with Cl//2 containing gases is studied for a variety of system parameters. Using a shielded configuration, the RIE is also studied as a function of substrate tilt angle. For normal ion incidence the etched walls generally slope away from the original mask edges. At lower pressures (approximately 1-2 m Torr) and higher temperatures and powers. The etch rate increases and the walls tend toward the vertical, but the surfaces become rougher. The shielded cathode results show little correspondence between the ion angle for maximum etch rate and the observed wall slopes, unlike analogous ion beam etching results. Vertical walls are possible by angling the substrates into the ion flux, and smoother walls are possible by rocking the substrate relative to the ion flux.