Investigation of high-temperature annealing and quenching effects on Al-nSi diodes by C-V and I-V measurements

Abstract

The behavior of Al-nSi diodes heat treatment above the eutectic temperature (600 °C) is studied by varying the annealing time and cooling rate. We have used the capacitance-voltage characteristic as a measure of the influence of the doping density and thickness of the recrystallized silicon layer at the interface. Poisson's equation is solved to obtain the C-V characteristic and to relate it to the effective barrier height. We find that the barrier height is independent of the annealing time, but it is a function of the cooling rate. It appears that the diffusion of aluminum into silicon does not play a significant role, but fast quenching tends to prevent aluminum from precipitation, so that the recrystallized silicon layer is highly doped.