Selective placement of quantum wells in flipchip light emitting diodes for improved light extraction

摘要

The present invention enhances the light extraction from the topside of the LED by an appropriate choice of the spacing from the active region to the reflective ohmic contact. Proper selection of the spacing from the active region to the reflective contact causes the interference pattern of upwardly-directed light to concentrate light within the escape cone for emission. Appropriate spacings are shown to be approximately lambdn/4, and to lie in the ranges 2.3 lambdn/4<=d<=3.1 lambdn/4 (favorably≈2.6 lambdn/4), and 4.0 lambdn/4<=d<=4.9 lambdn/4 (favorably≈4.5 lambdn/4). Extraction of light is thereby enhanced.