A Study of Surface Resistance of Si(100)

Although a Si(100) surface forms dimers to produce a stable structure, it contains defects such as steps which are thought to affect surface resistance. We measured the surface resistance of step-containing Si manufactured by an ordinary process, and discovered that Si exhibits angular characteristics (anisotropy). After performing measurements at 10° intervals over two revolutions of 360°, we found that the results are reproducible between the first and second turns, that the resistance is periodic with periods of 180° and 360°, and that the sheet resistances measured by the four-point-probe method are 7–13-fold greater than those calculated from the bulk resistance and thickness of the samples. Similar measurements were performed on step-free Si surfaces, which were found to exhibit almost no periodicity and had a sheet resistance is of 4–10-fold the bulk value. It was suggested that the periodicity of resistance is caused by the presence of many steps on the Si surface.