Photoluminescence and photoreflectance scanning of silicon-on-insulator materials

Proven to be useful for examining bonded SOI wafers are the photoluminescence (PL) and photoreflectance (PR) scanning. The strength in the bonded SOI approach lies in its flexibility in both the BOX and Si thicknesses and in the expected low defect densities in the Si layer. Problem areas include historically larger thickness variations and the difficult problem of 'voids' or bubbles between the two wafers due to particles present during the bonding.