Abstract: A quantum well intermixing (QWI) technique for modifying an energy bandgap during the formation of optical semi-conductor devices enables spatial control of the QWI process so as to achieve differing bandgap shifts across a wafer, device or substrate surface.

Abstract: A quantum well intermixing (QWI) technique for modifying an energy bandgap during the formation of optical semiconductor devices differing bandgap shifts across a wafer, device or substrate surface. The method includes: pattering the surface of a semiconductor substrate with QWI-initiating material in first regions of the surface; conducting a first thermal processing cycle on the substrate to generate a first bandgap shifts in the first regions; pattering the surface of the substrate with QWI initiating material in second regions of the surface, distinct from said first regions; and conducting a second thermal processing cycle on the substrate to generate a second bandgap shift in the second regions, and to generate a cumulative bandgap shift in the first regions, the cumulative bandgap shift being the cumulative result of said first and second thermal processing cycles. Further steps can produce additonal cumulative bandgap shifts.

Abstract: A method of performing quantum well intermixing in a semiconductor device structure uses a sacrificial part of a cap layer, that is removed after QWI processing, to restore the cap surface to a condition in which high performance contacts are still possible.