Fabrication of wafers with built-in areas of different bandgap materials is of paramount
importance for the technology of monolithically integrated devices. Numerous approaches have been
proposed and investigated in literature to address this problem especially in III-V basedsemiconductor
microstructures. We report on an innovative technique of post-growth selective area
bandgap engineering of InGaAsP/InP quantum well (QW) microstructures that is based on infrared
laser rapid thermal annealing (Laser-RTA). The method makes use of a 150 W 980 nm laser for
background heating of wafers to just below the threshold for quantum well intermixing (QWI)
temperatures. Another infrared source, a 30 W TEM00 Nd:YAG laser, is used to increase the
temperature above the QWI threshold that leads to the fabrication of different bandgap material.
The Laser-RTA technique allows for a significant reduction in the risk of damaging the surface of
a semiconductor wafer heated to high temperature with one laser source. Also, it has the potential to
fabricate almost arbitrary shaped lines of bandgap engineered material. For the investigated
GaInAsP/InP QW microstructures, we have achieved bandgap shifts in excess of 200 nm.
We discuss advantages that the proposed Laser-RTA technique offers in the fabrication of
monolithically integrated photonic devices.