Hot-carrier evaluation of a zero-cost transistor developed via process optimization in an embedded non-volatile memory CMOS technology

International audienceA new transistor architecture is developed by reusing already existing fabrication process bricks in an embedded nonvolatile memory (eNVM) sub-40 nm CMOS technology, resulting in a middle-voltage zero-cost transistor, ideal for lowcost products. TCAD simulations are undertaken to confirm the feasibility of the process optimization and predict the transistor performance. The new transistor is fabricated then electrically characterized. The new device shows good analogue performances for no cost added. A hot-carrier injection (HCI) degradation evaluation is performed and confirms the reliability of the device.

Effect of SET temperature on data retention performances of HfO2-based RRAM cells

International audienceIn this paper the effect of SET temperature on data-retention performances in HfO2-based RRAM has been thoroughly investigated. We demonstrated, for the first time to our knowledge, that high temperature programming (even if it has no influence on the initial resistance) has a strong effect on thermal stability of the conductive filaments. Moreover, we highlighted the impact of SET temperature also on RESET characteristics. We gathered all these experimental evidences under a simple modeling of the filament morphology, proving that the filament size might be tuned by adjusting the programming temperature. We conclude that reducing the conductive filament diameter while keeping high density of the oxygen vacancies significantly improves data retention. Index Terms— Resistive-switching random access memory (RRAM), data retention, temperature, modeling

Depressive Symptom Clusters in Relation to Body Weight Status:Results From Two Large European Multicenter Studies

Background: There is strong evidence for a bidirectional association between depression and obesity. Several biological, psychological, and behavior-related factors may influence this complex association. Clinical impression and preliminary evidence suggest that patients with a diagnosis of major depressive disorder may endorse very different depressive symptom patterns depending on their body weight status. Until now, little is known about potential differences in depressive symptoms in relation to body weight status. Objective: The aim of this analysis is the investigation of potential differences in depressive symptom clusters (mood symptoms, somatic/vegetative symptoms, and cognitive symptoms) in relation to body weight status. Methods: Cross-sectional baseline data were derived from two large European multicenter studies: the MooDFOOD Trial and the NESDA cohort study, including persons with overweight and obesity and normal weight reporting subthreshold depressive symptoms (assessment via Inventory of Depressive Symptomatology Self-Report, IDS-SR30). Different measures for body weight status [waist-to-hip ratio (WHR) and body mass index (BMI)] were examined. Propensity score matching was performed and multiple linear regression analyses were conducted. Results: A total of n = 504 individuals (73.0% women) were analyzed. Results show that more somatic/vegetative depressive symptoms, such as pain, change in appetite and weight, gastrointestinal symptoms, and arousal-related symptoms, were significantly associated with both a higher BMI and higher WHR, respectively. In addition, being male and older age were significantly associated with higher WHR. Mood and cognitive depressive symptoms did not yield significant associations for both body weight status measures. Conclusions: Somatic/vegetative symptoms and not mood and cognitive symptoms of depression are associated with body weight status. Thus, the results support previous findings of heterogeneous depressive symptoms in relation to body weight status. In addition to BMI, other body weight status measures for obesity should be taken into account in future studies. Clinical Trial Registration:www.ClinicalTrials.gov, identifier NCT02529423

Temperature impact (up to 200°C) on performance and reliability of HfO2-based RRAMs

International audienceThis paper provides an overview of the temperature impact (up to 200 °C) on the electrical behavior of oxide-based RRAM, during forming, low-field resistance reading, SET/RESET, disturb, data retention and endurance. HfO 2-RRAM devices (in a 1T1R configuration) integrated in an advanced 65 nm technology are studied for this aim. We show that forming operation is strongly activated in temperature (i.e.-0.5 V per hundred Celsius degree), being much less for SET and RESET voltages (i.e. <-0.05 V per hundred Celsius degree); disturb of HRS at fixed voltage showed to be independent of temperature; endurance up to 3.10 6 cycles, with optimized set of stress parameters showed no significant variation; data retention at 150 °C up to 68 days showed stable programming window, after different initial programming algorithms

Temperature impact (up to 200 \ub0C) on performance and reliability of HfO2-based RRAMs

This paper provides an overview of the temperature impact (up to 200 \ub0C) on the electrical behavior of oxide-based RRAM, during forming, low-field resistance reading, SET/RESET, disturb, data retention and endurance. . HfO2-RRAM devices (in a 1T1R configuration) integrated in an advanced 65 nm technology are studied for this aim. We show that forming operation is strongly activated in temperature (i.e. -0.5 V per hundred Celsius degree), being much less for SET and RESET voltages (i.e. < -0.05 V per hundred Celsius degree); disturb of HRS at fixed voltage showed to be independent of temperature; endurance up to 3.106 cycles, with optimized set of stress parameters showed no significant variation; data retention at 150 \ub0C up to 68 days showed stable programming window, after different initial programming algorithms

Experimental and Theoretical Study of Electrode Effects in HfO2 based RRAM

In this work, the impact of Ti electrodes on the electricalbehaviour of HfO2-based RRAM devices is conclusivelyclarified. To this aim, devices with Pt, TiN and Ti electrodeshave been fabricated. We first provide severalexperiments to clearly demonstrate that switching is driven bycreation-disruption of a conductive filament. Thus, the role ofTiN/Ti electrodes is explained and modeled based on thepresence of HfOx interfacial layer underneath the electrode. Inaddition, Ti is found responsible to activate bipolar switching.Moreover, it strongly reduces forming and switching voltageswith respect to Pt-Pt devices. Finally, it positively impacts onretention. To support and interpret our results we providephysico-chemical measurements, electrical characterization,ab-initio calculations and modeling