Critical assessment of birefringence imaging of dislocations in 6H silicon carbide

International audienceUsing 6H silicon carbide (6H-SiC) wafers including domains with different values of residual stress, the birefringence pattern of threading dislocations is measured and modeled. A quantitative fit of the birefringence pattern makes possible to identify the basal plane component of the Burgers vector with a reasonable accuracy, and we show that a varying level of residual stress over the SiC wafer results in substantial modifications of the birefringence patterns, which are well accounted for by the simulation. We compare birefringence data with etch pits formed after KOH etching, and critically assess the information which can be extracted from the combined use of both techniques. (C) 2012 Elsevier B.V. All rights reserved