Study of Hole Traps in the Oxide-Nitride-Oxide Structure of the SONOS Flash Memory

摘要

The origin and the locations of the hole traps in the oxide-nitride-oxide (ONO) structurefabricated on a p-type Si substrate were investigated by using capacitance-voltage (C-V) and deeplevel transient spectroscopy (DLTS) measurements. The C-V loop was used not only to evaluatethe memory effect of the ONO capacitor but also to determine suitable bias conditions for DLTS.Then, hole traps were found to be distributed over energy levels of 0.49~0.64 eV above thevalence band maximum of Si and their origin was attributed to a combination of nitride and theSiO_2/Si interface by using small-pulse DLTS and filling -bias- dependent DLTS techniques.