Nitride thickness dependence of trap generation and negative stress-induced current in oxidized nitride films (<5 nm)

Abstract The trap generation and negative stress-induced current in oxidized nitride films for two film thickness values have been investigated using MIS capacitors and p-channel MISFET transistors. It was already observed that in thin nitride film the gate current is two orders of magnitude larger than that for the thick film. But for a constant top oxide on the nitride films, the gate current was almost the same. After subjecting both films to a constant current stress, the gate current measured for the oxidized thick nitride film was larger than that of the oxidized thin nitride film. The hole and electron currents were measured independently before and after stress application. The current increase in oxidized thin nitride film is caused by the stress-induced generation of trapped electrons, while the current increase in the oxidized thick nitride film is caused by the stress-induced generation of trapped holes in the top-oxide film and in the bulk nitride.