Charging effects in Ge nanocrystals embedded in SiO2 matrix for non volatile memory applications

Charging effects in germanium nanocrystals (nc-Ge) embedded in SiO2 matrix fabricated by low pressure chemical vapor deposition have been studied by the mean of capacitance–voltage (C–V) combined with current–voltage (I–V) analysis. The C–V measurements showed hysteresis phenomena indicating holes charging in the Ge islands. The I–V measurements at ambient temperature exhibited an N-shaped form attributed to screening effects of positive charges stored in the nc-Ge. The same measurement at low temperatures shows that the hole trapping is a thermally activated process and the I–V analysis with different ramp rates were used in order to investigate the charging phenomena.