Electrical Properties of Amorphous Si-P/P-Type Si Schottky Barrier Contact

Abstract

Electrical properties of a contact between amorphous silicon-phosphorous solid solution film (a-Si-P) and p-type Si are described. This contact is basically a Schottky contact because a-Si-P is one of the Fermi glasses. Its current-voltage (I-V) and capacitance-voltage (C-V) characteristics, however, exhibit anomalous features differing from those of an ideal Schottky contact. In the I-V curves, the forward current saturates at around 0.4 V, followed by an exponential reincrease in current above 0.5 V. This is interpreted as a charge exchange between the interface states and a space-charge region formed in the a-Si-P electrode. In the C-V curves, an excess capacitance is observed even for reverse bias. The origin of this capacitance is also discussed.