Borderless silicon nitride defect behaviour and their influences on initial data loss in single polysilicon flash memories

摘要

Pre Metal Dielectric layer characterization by capacitance versus voltage hysteresis method has revealed the larger charge amount contained in the PECVD borderless silicon nitride. Its charges, attributed to K centers, exist under two states K~+ and K~- that can be cycled thanks to carrier injection or by direct transformation under thermal activation. Thus, this dielectric presents a memory like behaviour. Based on detailed characterization of charge exchange in this dielectric, a fast initial charge loss model is proposed in order to explain the fast charge losses observed during programming and erasing bake sequences on single polysilicon flash memories.