Fabrication of planar GaAs DH laser diodes on SI substrate

Abstract

Oxide stripe GaAs double heterostructure(DH) laser diodes were fabricated on semi-insulating(SI) GaAs substrate for optoelectronic integrated circuit(OEIC) applications in mind. $n^-$ -GaAs/n-GaAs/$n^+$ -GaAs/n-AlGaAs/p-GaAs/p-AlGaAs/$p^+$ -GaAs layers were grown on the SI substrate by liquid phase epitaxy technique. Active layer thickness is 0.6 um. The n-type ohmic contact was formed on the $n^+$ -GaAs layer after chemical etching of the upper four layers. Threshold current of 210 mA was obtained for the stripe width of 8 um and the cavity length of 340 um. This value corresponds to the threshold current density of 2700 A/㎠ of the broad-area-type laser, which is close to the theoretical value. To further lower the threshold current, the active layer thickness must be decreased to 0.2 um.