Chemical beam epitaxy of GaInP on GaAs(100) substrates and its application to 0.98 μm lasers

Abstract

We present results on the growth, doping, and application to lasers of GaInP on GaAs(100) substrates using chemical beam epitaxy (CBE). The growth studies were performed in the substrate temperature range of 490–555°C. We were able to obtain lattice-matching with good surface morphology over the entire substrate range investigated. For a fixed triethylgallium (TEGa) flow, a sharp increase in the trimethylindium (TMIn) flow required to obtain lattice-matching for T sub above 520°C is observed. This can be attributed to an increase in GaP growth rate and a decrease in InP growth rate due to desorption of TMIn species. The p-type and n-type doping of Ga 0.51In 0.49P was investigated using diethylzinc (DEZn) and hydrogen sulfide (H 2S), respectively. It was found that low substrate temperature (≲ 510°C) was necessary to obtain high p-type doping. Separate confinement heterostructure (SCH) lasers with strained In 0.2Ga 0.8As/GaAs multiple-quantum-well (MQW) active layers and Ga 0.51In 0.49P cladding layers for operation at 0.98 μm were grown. Broad-area lasers show extremely low threshold current densities, J th, of 70 A/cm 2. Ridge waveguide lasers with 4 μm stripe width have a threshold of 7.8 mA and gave linear CW output powers upto 100 mW. High external quantum efficiency of 0.9 mW/mA and a very low internal waveguide loss of 2.5 cm -1 were obtained from these lasers.