Electrical characterization of isoelectronic In-doping effects in GaN films grown by metalorganic vapor phase epitaxy

Indium isoelectronic doping was found to have profound effects on electrical properties of GaN films grown by metalorganic chemical vapor deposition. When a small amount of In atoms was introduced into the epilayer, the ideality factor of n-GaN Schottky diode was improved from 1.20 to 1.06, and its calculated saturation current could be reduced by 2 orders of magnitude as compared to that of the undoped sample. Moreover, it is interesting to note that In isodoping can effectively suppress the formation of deep levels at 0.149 and 0.601 eV below the conduction band, with the 0.149 eV trap concentration even reduced to an undetected level. Our result indicates that the isoelectronic In-doping technique is a viable way to improve the GaN film quality. (C) 2000 American Institute of Physics. [S0003-6951(00)04005-5].