Electron injection into ultrathin-SiO_2/(100) interfaces studied by scanning tunneling miroscopy/scanning tunneling spectroscopy

摘要

Dielectric degradation phenomenon of ultra-thin gate SiO_2 films is one of the most essential factors for the reliability of silicon-based devices such as dynamic-randomaccess memories (DRAMs). Although a number of studies on trap formation in ultrathin SiO_2 films have been reported using metal-oxide-semiconductor (MOS) capacitors, capacitance-voltage (C-V) or currentvoltage (I-V) characteristics of MOS capacitors show only averaged properties in the gate area. In order to relaize the further miniaturization of the devices, it is necessary to understand the degradation mechanism on an atomic scale. In this study, we have applied the combination of scanning tunneling spectroscopy (STS) as a new technique for quantitative evaluation of the trap formation in ultrathin SiO_2 films.