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

Abstract

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.