Correlation between charge trap distribution and memory characteristics in metal/oxide/nitride/oxide/silicon devices with two different blocking oxides, Al2O3 and SiO2

Abstract

We examined the origin of the charge traps in bothSiO(2)/Si3N4/SiO2 (ONO) and Al2O3/Si3N4/SiO2 (ANO) structures and their effect on the memory characteristics by capacitance-voltage (C-V) measurements and deep level transient spectroscopy (DLTS). A larger memory window was observed by C-V for ANO, due to its higher trap density. The DLTS showed that nitride traps are dominant in ANO, while more Si/SiO2 interface-related traps are observed in ONO. The ANO capacitor outperforms the ONO one in terms of both the program efficiency and retention, which is attributed to the reduced number of interface traps in ANO. (C) 2008 American Institute of Physics.