Tunneling Current Modulation By Ge Incorporation Into Si Oxide Films For Flash Memory Applications

Current-voltage characteristic for a Ge-incorporated Si oxide was investigated. Current enhancement was observed for the electric field larger than 10 MV/cm. Such a current enhancement only under high electric field is expected to improve programming performance without deteriorating reading performance. From secondary ion mass spectrometry and hard x-ray photoelectron spectroscopy analyses and current simulation, it is concluded that the Ge impurity in Ge4+ state around the tunnel oxide/substrate interface enhances the current by trap-assisted tunneling. The programming current enhancement induced by the Ge incorporation is expected to be one of the promising solutions for the next-generation flash memory. (C) 2012 American Institute of Physics. [doi:10.1063/1.3687189]