A review will be given of plasma chemistries for etching AlGaN/InGaN, InP/InGaAsP and AlGaAs/GaAs diode lasers and light-emitting diodes. With Cl@sub 2@-based chemistires, it is generally necessary to heat the sample when etching In-containing compounds, because of the low volatility of InCl@sub x@. By contrast, the use of Br@sub 2@ or I@sub 2@ based chemistries produces practical etch rates at room temperature. Plasma-induced damage can play a significant role in determining device performance through effects on ohmic contact resistances or optical output power. Special attention must be paid to the quality of the initial lithography for patterning resist, since sidewall roughness is transferred into the semiconductor during subsequent etching. Gratings for DBR or DFB layers are also readily created using holographic lithography and plasma etching.