XAFS atomistic insight of the oxygen gettering in Ti/HfO2 based OxRRAM

Hafnia-based resistive memories technology has come to maturation and acceded to the market of nonvolatile memories. Nevertheless, the physical mechanisms involved in resistive switching are not yet fully understood and the numerous ab initio simulations studies have few many atomic-scale experimental counterparts. In this study we investigate the oxygen migration mechanism from an amorphous HfO2 layer to the Ti cap layer at a local scale before and after a thermal treatment. X-ray absorption spectroscopy at the Ti K edge and Hf L(III )edge has been performed on samples as-deposited and annealed in Ar at 400 degrees C to mimic the back-end-of-line thermal budget (BEOL) of CMOS technology. The short-range Ti and Hf environments have been determined, showing that annealing promotes the migration of O from HfO2 to Ti, the amount of which is quantified. This provokes an expansion and an increase of atomic disorder in the Ti lattice. The nature of the oxygen gettering mechanism by the Ti metal is understood by comparing samples with increasing Ti-capping thickness. We show that the Ti getter effect has to be activated by thermal treatment and that the O diffusion takes place in a region of a few nanometers close to the Ti/HfO2 interface. Therefore, the thermal budget history and the Ti cap-layer thickness determine the oxygen vacancy content in the HfO2 layer, which in turn controls the electrical properties, especially the forming operation

Ovarian-Adnexal Reporting Data System Magnetic Resonance Imaging (O-RADS MRI) score for risk stratification of sonographically indeterminate adnexal masses.

Importance: Approximately one-quarter of adnexal masses detected at ultrasonography are indeterminate for benignity or malignancy, posing a substantial clinical dilemma. Objective: To validate the accuracy of a 5-point Ovarian-Adnexal Reporting Data System Magnetic Resonance Imaging (O-RADS MRI) score for risk stratification of adnexal masses. Design, Setting, and Participants: This multicenter cohort study was conducted between March 1, 2013, and March 31, 2016. Among patients undergoing expectant management, 2-year follow-up data were completed by March 31, 2018. A routine pelvic MRI was performed among consecutive patients referred to characterize a sonographically indeterminate adnexal mass according to routine diagnostic practice at 15 referral centers. The MRI score was prospectively applied by 2 onsite readers and by 1 reader masked to clinical and ultrasonographic data. Data analysis was conducted between April and November 2018. Main Outcomes and Measures: The primary end point was the joint analysis of true-negative and false-negative rates according to the MRI score compared with the reference standard (ie, histology or 2-year follow-up). Results: A total of 1340 women (mean [range] age, 49 [18-96] years) were enrolled. Of 1194 evaluable women, 1130 (94.6%) had a pelvic mass on MRI with a reference standard (surgery, 768 [67.9%]; 2-year follow-up, 362 [32.1%]). A total of 203 patients (18.0%) had at least 1 malignant adnexal or nonadnexal pelvic mass. No invasive cancer was assigned a score of 2. Positive likelihood ratios were 0.01 for score 2, 0.27 for score 3, 4.42 for score 4, and 38.81 for score 5. Area under the receiver operating characteristic curve was 0.961 (95% CI, 0.948-0.971) among experienced readers, with a sensitivity of 0.93 (95% CI, 0.89-0.96; 189 of 203 patients) and a specificity of 0.91 (95% CI, 0.89-0.93; 848 of 927 patients). There was good interrater agreement among both experienced and junior readers (κ = 0.784; 95% CI, 0.743-0824). Of 580 of 1130 women (51.3%) with a mass on MRI and no specific gynecological symptoms, 362 (62.4%) underwent surgery. Of them, 244 (67.4%) had benign lesions and a score of 3 or less. The MRI score correctly reclassified the mass origin as nonadnexal with a sensitivity of 0.99 (95% CI, 0.98-0.99; 1360 of 1372 patients) and a specificity of 0.78 (95% CI, 0.71-0.85; 102 of 130 patients). Conclusions and Relevance: In this study, the O-RADS MRI score was accurate when stratifying the risk of malignancy in adnexal masses

Efficient Production of HIV-1 Virus-Like Particles from a Mammalian Expression Vector Requires the N-Terminal Capsid Domain

It is now well accepted that the structural protein Pr55Gag is sufficient by itself to produce HIV-1 virus-like particles (VLPs). This polyprotein precursor contains different domains including matrix, capsid, SP1, nucleocapsid, SP2 and p6. In the present study, we wanted to determine by mutagenesis which region(s) is essential to the production of VLPs when Pr55Gag is inserted in a mammalian expression vector, which allows studying the protein of interest in the absence of other viral proteins. To do so, we first studied a minimal Pr55Gag sequence called Gag min that was used previously. We found that Gag min fails to produce VLPs when expressed in an expression vector instead of within a molecular clone. This failure occurs early in the cell at the assembly of viral proteins. We then generated a series of deletion and substitution mutants, and examined their ability to produce VLPs by combining biochemical and microscopic approaches. We demonstrate that the matrix region is not necessary, but that the efficiency of VLP production depends strongly on the presence of its basic region. Moreover, the presence of the N-terminal domain of capsid is required for VLP production when Gag is expressed alone. These findings, combined with previous observations indicating that HIV-1 Pr55Gag-derived VLPs act as potent stimulators of innate and acquired immunity, make the use of this strategy worth considering for vaccine development

0.12 µm GATE LENGTH In0.52Al0.48As/In0.53Ga0.47As HEMTs on transferred substrate

New In0.52Al0.48As/In0.53Ga0.47As transferred-substrate high electron mobility transistors (TS-HEMTs) have been successfully fabricated on 2 inch Silicon substrate with 0.12 µm T-shaped gate length. These new TS-HEMTs exhibit typical drain currents of 450 mA/mm and extrinsic transconductance up to 770 mS/mm. An extrinsic current cutoff frequency fT of 185 GHz is obtained. That result is the first reported for In0.52Al0.48As/In0.53Ga0.47As TS-HEMTs on Silicon substrate

Etude des structures MIS sur InP réalisées avec une double couche anodique

Des composants MISFET de bonne qualité sont obtenus avec une double couche alumine-oxyde natif comme isolant de grille. Dans cet article, la loi de croissance de ces deux couches et la composition chimique de l'oxyde interfacial sont étudiées par ellipsométrie et XPS. L'oxyde natif est très proche de In (PO3)3. La comparaison des courbes capacité-tension montre que l'oxyde interfacial doit être plus épais que 5 nm pour obtenir de bonnes propriétés électriques

Etude des structures MIS sur InP réalisées avec une double couche anodique

High quality InP MISFET's with Al2O3/native oxide double layer as gate insulator have been reported. In this paper, the oxide growth law of the double layer and the chemical composition of the interfacial oxyde are studied using ellipsometry and XPS. The native oxide is found to be very similar to In(PO3)3. Capacitance-voltage measurements revealed that the thickness of this interfacial oxide must be thicker than 5 nm to obtain the best electrical properties for the interface.Des composants MISFET de bonne qualité sont obtenus avec une double couche alumine-oxyde natif comme isolant de grille. Dans cet article, la loi de croissance de ces deux couches et la composition chimique de l'oxyde interfacial sont étudiées par ellipsométrie et XPS. L'oxyde natif est très proche de In (PO3)3. La comparaison des courbes capacité-tension montre que l'oxyde interfacial doit être plus épais que 5 nm pour obtenir de bonnes propriétés électriques

Ag/HfO2-based conductive bridge memories elaborated by atomic layer deposition: impact of inert electrode and HfO2 crystallinity on resistive switching mechanisms

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Quand peut-on classer ACR 4, 5, 0 après l'IRM ?

International audienceL’IRM mammaire est un examen de seconde intention au décours duquel il est important d’utiliser une conclusion adéquate qui permette de gérer au mieux l’ensemble du dossier sénologique de la patiente. Ainsi, il est important de limiter au maximum le classement Birads 0 et d’utiliser à bon escient les classements Birads 4 et Birads 5. Les masses de contours non lisses, se rehaussant selon une courbe de type 3 ou selon une topographie annulaire, ainsi que les non masses de distribution galactophorique, de type micronodulaire ou annulaire, doivent être classées au moins Birads 4. Une masse ayant des contours spiculés peut être classée ACR4 si ce critère est le seul critère suspect ou ACR5 si d’autre(s) critère(s) suspect(s) sont associé(s)