Abstract: A semiconductor laser diode includes two semiconductive cladding layers of different conductivity types, which are stacked on a substrate. An active layer of an undoped semiconductor film is sandwiched between the cladding layers. A channel groove is formed in a current blocking layer and the underlying cladding layer, to be deep enough to cause the current blocking layer to be divided into two parts. A waveguide layer covers the channel groove and the current-blocking layer, to provide a slab-coupled waveguide structure for transverse mode oscillation. The second cladding layer, the current-blocking layer, and the waveguide layer are composed of gallium arsenide containing aluminum.

Abstract: A compound semiconductor is dry-etched by introducing a plasma-generating gas comprising boron trichloride and chlorine into a plasma generation region which is defined between a cathode for supporting a workpiece comprising a compound semiconductor and an anode opposite thereto. High-frequency electric power is applied between the cathode and the anode, thereby generating a plasma from the introduced plasma-generating gas. The compound semiconductor is etched with the thus formed plasma.