We directly evaluated the effect of dislocations on current-voltage (I-V) characteristics of Au/Ni contacts formed on n-GaN grown by metalorganic chemical. vapor deposition. The key feature of our evaluation is the combination of submicrometer Schottky dot array formation by electron-beam lithography and I-V measurement by atomic force microscopy with a conductive probe. The sample, which has a free electron concentration of 3 x 10(17) cm(-3), showed that neither mixed nor pure edge dislocations affect the I-V characteristics (Schottky barrier height, ideality factor, and reverse leakage cur-rent). Possible models to explain the results are discussed. On the other hand, it was found that a large structural defect with a diameter of a few hundred nanometers shorted the contact. The density, however, was less than 4 x 10(5) cm(-2). These results indicate that, in fabricating short-gate field-effect transistors, gate Schottky contacts containing dislocations should not be considered a problem with respect to uniformity and reproducibility. (C) 2003 American Vacuum Society.