Anomalous capacitance-voltage characteristics of Al/Al-rich Al2 O3 /p-Si capacitors and their reconstruction

Anomalous capacitance-voltage (C-V) characteristics of Al/Al-rich Al2 O3 /p-Si capacitors have been observed. The measured C-V curves exhibit rolloffs and frequency dispersion in the accumulation region and voltage stresses cause both horizontal and vertical shifts of the C-V curves. These anomalous behaviors are mainly due to the large current conduction and the charge trapping in the Al-rich Al2 O3 layer. The anomalous C-V characteristics have been reconstructed based on a four-element circuit model. With the reconstructed C-V curves, the capacitance of the Al-rich Al2 O3 layer and the charging-induced flatband voltage shift can be determined.