The resistance of alloyed In-GaN ohmic contacts was studied experimentally. At 180 to 320K, the resistance per unit area increased with temperature. This was typical of metallic conduction and disagreed with current-flow mechanisms which were associated with thermionic, field-effect or thermal field emission. It was assumed that In-GaN ohmic contacts were formed by conducting shunts which arose due to the precipitation of In atoms on dislocations. As deduced from the temperature dependence of the contact resistance, the number of shunts per unit contact area was of the order of 107 to 108/cm2. This was close to the dislocation density, of 108/cm2, which had been measured in the initial material.

The Mechanism of Current Flow in an Alloyed In-GaN Ohmic Contact. T.V.Blank, Y.A.Goldberg, O.V.Konstantinov, V.G.Nikitin, E.A.Posse: Semiconductors, 2006, 40[10], 1173-7