Carbon‐doped impurity induced layer disorder 0.98 μm lasers

We have fabricated high power carbon‐doped InGaAs/AlGaAs lasers using an impurity‐induced layer disordering process to define the active region. The advantage of carbon doping is that it exhibits significantly lower diffusivity compared to other p‐type dopants, thereby avoiding displacement of the p‐n junction, even at the high temperatures and long diffusion times required by the disordering process. Secondary ion mass spectrometry (SIMS) measurements before and after Si diffusion show the p‐n junction position to be unchanged during processing. The carbon was introduced using CCl4 as an extrinsic precursor, giving improved control over doping levels and ternary growth conditions that is not available with intrinsic carbon doping. Thresholds of 20 mA and slope efficiencies of 0.44 mW/mA at 25 °C were obtained for lasers with cavity lengths of 500 μm and coated facets.