Investigation of the surface roughness of CdZnTe substrates by different techniques of nanometer accuracy

The results of measurements of the root-mean-square (rms) surface roughness of CdZnTe substrates by confocal microscopy (CM), atomic force microscopy (AFM), and X-ray reflectometry (XRR) are compared. It is determined that CM yields the highest rms roughness values, AFM assumes an intermediate position, and XRR measurements produce results that are an order of magnitude lower than those obtained with the use of the other two techniques. It is demonstrated that CM rms roughness values depend to a considerable extent on the type of the microscope objective used in experiments. Probable reasons for the discrepancy between the obtained results are discussed.