Design and fabrication of VCSELs with AlxOy-GaAs DBRs

A procedure for fabricating vertical-cavity surface-emitting lasers (VCSELs) with oxide-based distributed Bragg reflectors (DBRs) is presented. An in-depth analysis of parameters and behavior unique to oxide VCSELs determines the device design. The development cycle time for these devices is reduced through development of a method for post-growth analysis of the epitaxial stack reflectivity before device processing. Threshold currents as low as 160 μA and resistances as low as 80 Ω are demonstrated using different device designs. The total optical loss of low-doped oxide VCSEL structures is 0.163% which is comparable to VCSEL designs based on all-semiconductor DBRs. The thermal resistance of an 8×8 μm VCSEL is measured to be 2.8°C/mW, demonstrating that the presence of oxide layers does not act as a barrier to heat flow out of the active region