Temperature dependence of Ohmic contacts of In0.83Ga0.17As photodiodes and its correlation with interface microstructure

The temperature-dependent electrical properties of Au Ohmic contacts of In0.83Ga0.17As photodiodes were systematically investigated in the temperature range 163–373 K. For two annealed sample, the novel temperature behavior of the specific contact resistivity ρ sc was observed and exhibits similarity to that of ‘metal,’ describable by a T 2.01 and T 2.19 dependence. The microscopic interfacial analysis from transmission electron microscope (TEM) indicated that the Au protrusions penetrating into the contact layer, with a density of 9 × 107 and 2.0 × 108 cm−2, respectively, could cause this phenomenon by acting as the more efficient conduction channels. By fabricating the extended wavelength In0.83Ga0.17As photodiode and deducing the series resistance from the current–voltage–temperature (I–V–T) characteristics, it is proved that the series resistance is mainly caused by the contact resistance of the metal–semiconductor (MS) interface. The results are very meaningful for the application of the extended wavelength In0.83Ga0.17As photodiode.