High-contrast microscopy of semiconductor and metal sites in integrated circuits by detection of optical feedback

High-contrast microscopy of semiconductor and metal sites in integrated circuits is demonstrated with laser-scanning confocal reflectance microscopy, one-photon (1P) optical-beam-induced current (OBIC) imaging, and detection of optical feedback by means of a commercially available semiconductor laser that also acts as an excitation source. The confocal microscope has a compact in-line arrangement with no external photodetector. Confocal and 1P OBIC images are obtained simultaneously from the same focused beam scanned across the sample plane. Image pairs are processed to generate exclusive high-contrast distributions of semiconductor, metal, and dielectric sites in a GaAs photodiode array sample.