Impact of lateral charge migration on the retention performance of planar and 3D SONOS devices

This paper investigates the impact of lateral charge migration on the retention performance of charge-trap memories whose storage layer is not patterned self-aligned with the channel area of each cell. Experimental results on planar SONOS devices, revealing an important contribution of lateral charge migration at 150 °C, are used to calibrate a new numerical model accounting for both the vertical and the lateral charge loss from the silicon nitride. Modeling results allow a detailed analysis of the retention transients of both planar and 3D SONOS arrays, evaluating, for the latter, the minimum dimensions needed to fulfill the retention requirements at 85 °C.