Current conduction in Al/Si nanocrystal embedded $SiO2/p-Si$ diodes with various distributions of Si nanocrystals in the oxide

Different distributions of Si nanocrystals (nc-Si) in the gate oxide of Al/nc-Si embedded $SiO2/p-Si$ diodes are synthesized with Si ion implantation technique. Current conduction in the diodes with different nc-Si distributions has been investigated. It is shown that under a positive gate bias Fowler–Nordheim (FN) tunneling from the Si substrate to the oxide, the nanocrystal-assisted conduction (e.g., tunneling, Frenkel–Poole emission) and the nanocrystal-assisted FN tunneling contribute to the current conduction depending on both the nc-Si distribution and magnitude of the gate bias. In the case that nc-Si is densely distributed throughout the oxide, a huge enhancement in the current conduction is observed as a result of the formation of many percolative conduction paths by the nc-Si connecting the gate to the Si substrate.