Showing papers by "Jean-Michel Portal published in 2016"

A multi-scale methodology connecting device physics to compact models and circuit applications for OxRAM technology

Abstract: RRAM technology relying on transitional metal oxides (namely OxRAM) is about to reach the industrial stage. Nevertheless the physical-based understanding of the material and process implications at device and circuit levels is still not completely clear, hindering the full industrial exploitation of the OxRAM technology. In this context, this article presents a multi-scale methodology that connects the microscopic material properties to the electrical behavior of OxRAM devices at the circuit level. Microscopic models describing OxRAM operation (i.e., forming, resistive switching) and variability (e.g., cycle-to-cycle, RTN) will be reviewed and used for the development of compact models that will allow investigating the potential of this technology at the circuit level. An overview of some innovative applications involving OxRAM will be finally presented.

Ultra Low Power Charge Pump with Multi-Step Charging and Charge Sharing

Abstract: a new approach for improving the power efficiency of the conventional four-phase charge pump is presented. Based on the multi-step capacitor charging and the charge sharing concept, the charge pump design is able to reduce the overall power consumption by 35% compared to the conventional four-phase charge pump and by 15% compared to a charge sharing charge pump, for an output current of 200μA with 12V output voltage.

NVM cell degradation induced by femtosecond laser backside irradiation for reliability tests

Abstract: In this paper we present the behavior of a single nonvolatile Flash floating gate memory cell when it is irradiated, from the backside, by femtosecond laser pulses. For the first time we show that the memory cell state can change using this type of stimulation. The measurements were carried out with an experimental setup with an ad hoc probe station built around the optical bench. We present the experimental results using different memory bias conditions to highlight the charge injection in the floating gate. Then, we study the cell degradation to check the state of the tunnel oxide and the drain-bulk junction. The aim is to understand the failure mechanisms and use this technique for accelerated reliability tests. Finally we report the experimental results achieved for different laser energies.

Non-volatile memory with programmable resistance

Abstract: L'invention concerne une memoire non volatile comprenant une pluralite de cellules elementaires (300), chaque cellule comportant : un premier element de stockage (101) a resistance programmable connecte entre des premier (SL ; DL) et deuxieme (n) noeuds de la cellule ; un premier transistor d'acces (103) reliant le deuxieme noeud (n) a un troisieme noeud (BL) de la cellule ; et un deuxieme transistor d'acces (305) reliant le deuxieme noeud (n) a un quatrieme noeud (DL ; SL) de la cellule.

Electromagnetic Analysis Perturbation using Chaos Generator

Abstract: Cryptographic algorithms albeit mathematically sure may have security breaches when implemented on hardware chips. There are several ways to compromise their security, one method is to analyze their electromagnetic (EM) emissions in order to find secrets (cryptographic keys for example). This paper proposes a proof of concept of a countermeasure against these attacks, it is based on a chaotic oscillator coupled with an antenna to blur the EM emissions of the chip. The objective is to generate EM noise within the chip with an internal system in order to make the secret information harder to extract. A testchip was developed and tested in conditions as close as possible to real usecase to prove the relevance of the concept. The EM field collected while running the chip were superposed to AES (Advanced Encryption Standard) emissions collected using a similar setup to test the disturbing effect of the noise on a CPA, a classic attack to retrieve AES keys. The experiment shows that it can effectively increase the difficulty of finding the keys, proving that the basic concept and the developed chip can be used as a countermeasure for EM analysis attacks.