The stability of electrical characteristics of Ti/n-Si/Ag,Ti/n-Si/Cu and Ti/n-Si/AgCu diodes prepared under the same conditions with respect to increasing aging time

The purpose of this study is to fabricate Ti/n-Si/Ag, Ti/n-Si/Cu and Ti/n-Si/AgCu Schottky type diodes and to investigate the effects of aging time on the diode parameters such as ideality factor, barrier height, series resistance, interface state density and rectification ratio. High purity titanium (Ti) metal was deposited on the back side of the n-Si semiconductor and then the Ti/n-Si junction was annealed at 420 °C in nitrogen atmosphere. This junction showed ohmic behavior. To fabricate rectifier contacts, Ag, Cu metals and AgCu alloy have been evaporated on the other polished surface of n-Si with Ti ohmic contact. Ag and Cu ratios in the AgCu alloy which are used in the process of preparing the Schottky contact were taken in equal weights. Thus, Ti/n-Si/Ag, Ti/n-Si/Cu and Ti/n-Si/AgCu Schottky type diodes were prepared under the same conditions. The current-voltage (I-V) characterization of Ti/n-Si/Ag, Ti/n-Si/Cu and Ti/n-Si/AgCu diodes were immediately made at room temperature in dark conditions. To investigate the effect of aging time, the I-V measurements of the diodes have been repeated after 1, 7, 15, 30 and 90 days. Characteristic parameters of the diode were calculated from the I-V measurements which are taken with respect to aging time. The results were compared. From these results, it can clearly be seen that the electrical characteristics of diode which is made from AgCu alloy are more stable than other two diodes.