Fabrication of low-threshold voltage micro-lasers

The voltage required for threshold in vertical cavity surface emitting lasers (VCSELs) has been reduced to 1.7 V. Molecular beam epitaxy (MBE) was used to grow 30 pairs of n-doped AlGaAs/AlAs bottom mirrors and the active p-n junction with a 1- mu m p-doped top contact. Twelve pairs of alternating SiO/sub 2//Si/sub 3/N/sub 4/ layers formed a high-reflectivity mirror which was used to complete the laser cavity. It is shown that the combination of high-reflectivity dielectric mirror layers with accurate MBE growth can be used to significantly reduce the power requirements of individual laser elements. It is expected that this advance will allow one to integrate large numbers of VCSEL devices into complex arrays without the heat-dissipation problems found in more conventional VCSEL designs. Finally, the relatively shallow depth of the active area from the semiconductor surface allows one to greatly simplify the VCSEL fabrication process.