Abstract: In-containing III/V semiconductor materials (e.g., InGaP) can be dry etched in BCl.sub.3 in ECR apparatus. We have discovered that addition of N.sub.2 to the BCl.sub.3 can result in substantially higher etch rate (e.g., more than 50% higher). Etching is substantially without incubation period, and the resulting surface can be very smooth (e.g., RMS roughness less than 5 nm, even less than 2.5 nm). Exemplarily, the novel etching step is used in the manufacture of a InGaP/GaAs transistor.

Abstract: This invention pertains to buried heterostructure lasers which have been fabricated using a single step MOCVD growth of an MQW laser structure over a pattern etched GaAs substrate. The wet chemical etching of grooves having a dovetailed cross-section and being parallel to the [011] direction in GaAs substrates produced reentrant mesas which resulted in isolated laser active regions buried by the AlGaAs cladding layer. The 250 .mu.m long uncoated lasers emit at about 1 .mu.m. Lasers with coated facets have threshold currents of 20 mA and emit >100 mW per facet under room temperature operation. The external differential quantum efficiency for currents of from 30 mA to about 50 mA is found to be nearly independent of temperature in the range of 10.degree. C. to 90.degree. C. suggesting a low temperature dependence of leakage current.