Experimental study of carrier transport in multi-layered structures

Gate stress measurements are applied to Flash cell array structures. The counter intuitive V_t shift is associated to the charge redistribution in the ONO layer. This redistribution of charge follows Poole–Frenkel conduction mechanisms. In multi-level Flash, the total charge in the nitride layer need to be minimized, and well-controlled, in order to achieve good data retention of the device.