Temperature Dependence of Electrical Characteristics of Al/p-Si Shottky Barrier Diodes

Metal-semiconductor Schottky junctions as intricate part of semiconductor devices have been interested in the electronics industry. In this paper, Al/p-Si Schottky diodes which fabricated onto acceptor type silicon substrate using thermal evaporation layer deposition, were characterized in terms of thermionic emission theory. Ideality factor, reverse saturation current, Schottky barrier height, of the annealed diodes at the 150-350 °C temperature range, have been determined by measuring the current –voltage (I-V) characteristics. The effects of annealing process on the Schottky parameters have been inspected and it was found that the optimum annealing temperature was 250 °C. Then current-voltage characteristics of the processed diodes have been measured at 15 -300 °K sample temperature. Ideality factor, Schottky barrier height, and reverse saturation current and their temperature dependence have been determined. It was revealed that as the sample temperature decreases, the barrier height decreases while ideality factor increases. Finally, the Schottky barrier and Richardson coefficient have been determined taking into account the Gaussian distribution of barrier height. The unexpected high value of ideality factor can be justified in terms of ionized impurity scattering of carriers from diffused Al atoms to semiconductor near the Al/Si interface.