Effects of recombination current on the current–voltage characteristics in metal–InGaAs Schottky diodes

Current transport mechanisms were investigated on metal–InGaAs Schottky diodes in which the metal electrodes were deposited at both room temperature and low temperature. Based on fitting of the current–voltage $\mathrm{(I–V)}$ characteristics at different temperatures, it was found that the recombination current in the depletion region caused by the deep defect centers was responsible mainly for the deviations of $\mathrm{I–V}$ characteristics from the pure thermionic emission mechanism. This effect became more significant for diodes with lower barrier height, under smaller forward bias and at lower measuring temperature. However, the generation current only had subtle influence on the reverse bias characteristics. A deep defect level located at 0.321 eV below the bottom of the conduction band in the InGaAs material, which was identified by the deep level transient spectra measurements, may act as the recombination–generation deep center. The generation lifetime of this deep center may be much longer than its recombination lifetime, therefore it may more severely affect the forward biased $\mathrm{I–V}$ characteristics.