Charging-induced changes in reverse current-voltage characteristics of Al/Al-Rich Al₂O₃/p-Si Diodes

An Al-rich Al₂O₃ thin film was deposited on a p-type silicon substrate by radio frequency sputtering to form Al/ Al-rich Al₂O₃/p-Si diodes. The current-voltage (I-V) characteristics of the diodes were determined by carrier injection from either the Si substrate or the Al gate and by carrier transport along the tunneling paths formed by Al nanocrystals distributed in the oxide layer. The reverse I-V characteristics were greatly affected by the charge trapping in the oxide layer, i.e., the electron trapping significantly reduced the reverse current while the hole trapping enhanced the current significantly. However, the charge trapping did not produce a large change in the forward I-V characteristic.