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 10degrees intervals over two revolutions of 360degrees, we found that the results are reproducible between the first and second turns, that the resistance is periodic with periods of 180degrees and 360degrees, 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.