NATIVE-OXIDE DEFINED RING CONTACT FOR LOW-THRESHOLD VERTICAL-CAVITY LASERS

Data are presented characterizing a new process for fabrication of ver tical-cavity surface-emitting lasers based on the selective conversion of high Al composition epitaxial AlGaAs to a stable native oxide usin g ''wet oxidation.'' The native oxide is used to form a ring contact t o the laser active region. The resulting laser active regions have dim ensions of 8, 4, and 2 mum. The lowest threshold laser is achieved wit h the 8-mum active region, with a minimum threshold current of 225-muA continuous wave at room temperature.