Full Recess Integration of Small Diameter Low Threshold VCSELs within Si-CMOS ICs

Oxide-aperture vertical-cavity surface-emitting lasers (VCSELs) have been integrated as individual device pills within the dielectric stacks of commercially produced silicon integrated circuits and monolithically connected electrically with the underlying circuitry using technology compatible with wafer-scale processing. The 55 microm diameter, 8 microm tall device pills were bonded in recesses etched to reveal buried contact/bond pads included in the IC layout; the surface was replanarized, contact vias formed, and interconnect metal deposited and patterned. The typical CW threshold current, 1 to 2.5 mA, was the same before and after integration, and integrated devices had thermal impedances similar to devices on their native GaAs substrates.