A New Method to Extract the Charge Centroid in the Program Operation of Metal-Oxide-Nitride-Oxide-Semiconductor Memories

We proposed and demonstrated a new method to extract the charge centroid of metal-oxide-nitride-oxide-semiconductor (MONOS) devices. Comparing with other existing methods for charge centroid evaluation, our new method has the advantage of simplicity and the compatibility with other test sequences of memory cell capacitors. Using our method, we investigated the dependence of charge centroid on the thickness of SiN layer. It is found that the charge centroid of the 14-nm-thick SiN MONOS is located around the middle of the SiN layer, while the 5-nm-thick SiN MONOS has the centroid at the SiN/Al2O3 interface. These results indicate that the available trap sites during program operation are dependent on the thickness of the SiN layer. (C) 2010 The Japan Society of Applied Physics