Reliability Issues Related to Fast Charge Loss Mechanism in Embedded Non Volatile Memories

In this work, we report on a thorough study of charge loss in embedded non volatile memories. We focused on the fast initial threshold voltage (Vth) shift, which occurs during the first minutes of data retention bake. Experiments were performed to have a better understanding of this phenomenon. As a result, we can predict the Vth shift of a cell baked at 250degC and evaluate its impact on product reliability. This is the first time that this reliability aspect is characterized with such a level of accuracy. Based on these observations, a physical model is proposed to describe the fast initial threshold voltage shift