Scanning Internal-Photoemission Microscopy: New Mapping Technique to Characterize Electrical Inhomogeneity of Metal-Semiconductor Interface

A new mapping technique, termed scanning internal-photoemission microscopy, has been presented to characterize the electrical inhomogeneity of metal-semiconductor interfaces. To obtain images of a Schottky barrier height, we have used two laser beams in a 1 µm band for which Si and GaAs substrates are transparent, and thus the proposed technique has been capable of probing the metal-semiconductor interfaces directly. The capability of this microscopy has been demonstrated by visualizing the parallel contact with two different metals, the existence of mechanical damage, and an ultrathin layer buried beneath a thick metal.