Lateral redistribution of trapped charges in nitride/oxide/Si (NOS) investigated by electrostatic force microscopy

Charge decay and lateral spreading properties were characterized by modified electrostatic force microscopy (EFM) under a high vacuum at elevated temperatures. Variations in the charge profiles were modeled with the maximum charge density (ρ(m)) and the lateral spreading distance (Δ(s)), as extracted from the EFM potential line profiles. The scaling limitation of nitride trap memory is discussed based on the projected lateral spreading distances for holes and electrons, which were determined to be approximately 18 nm and 12 nm, respectively, at room temperature.