Electrical characteristic of metal-oxide-semiconductor with NiSi$_{2}$ nanocrystals embedded in oxide layer

The nano-structured electronic devices have received more attention recently. Metal-oxide-semiconductor structure with NiSi$_{2}$ nanocrystals embedded in the oxide layer, HfO$_{2}$/SiO$_{2}$, has been fabricated. Comparing with conventional ones, it could be operated under lower voltage and faster program/erase speed and has better endurance and retention. We have measured the temperature-dependent tunneling V-I curve on these HfO$_{2}$/SiO$_{2}$ nano-structured devices for the temperature from 1.2K to 300K. The results show an abnormal electrical characteristic. The tunneling V-I characteristics appear a new threshold voltage in the low temperature region, from 30K to 100K, while applied a negative voltage. The abnormal threshold voltage disappears when the temperature higher than 150K or lower than 30K. We attribute the new threshold voltage to the discrete quantum states of NiSi$_{2}$ nanocrystals in the oxide layer.