Characterization of thin bonded silicon-on-insulator structures by the microwave photoconductivity decay method

Thin silicon-on-insulator (SOI) layers of 0.5–2 µ m thickness are characterized by the microwave photoconductivity decay (µ-PCD) method with an N 2 laser as the excitation source. The penetration depth of the N 2 laser light is less than 0.1 µ m, and thus the excess carriers are excited only in the SOI layers. The measured recombination lifetime is sensitive to SOI thickness and interface properties, and thus the µ-PCD method can be used for characterization of the interface and observation of thickness variation. The surface (interface) recombination is considered as the dominant recombination mechanism.