Reliability of embedded SONOS memories

Abstract

In this work, arrays of two transistor (2T) and compact SONOS memory cells are presented together with an extensive reliability investigation. SONOS, which stands for semiconductor-oxide-nitride-oxide-semiconductor, is a non-volatile memory concept, which has recently regained strong attention because floating gate flash has reached its scaling limits. The better scaling perspective, together with the ease of integration in a base line CMOS process, makes SONOS an excellent candidate for embedded flash in future CMOS generations. This is especially true for the compact cell variant, which consists of a merged access gate (AG) and control gate (CG), giving extra advantages like smaller cell size and the reduction of short channel effects compared with the discrete two transistor variant.