Influence of active electrode impurity on memristive characteristics of ECM devices

Memristive devices are promising candidates for the implementation in more than Moore applications. Their functionalities, electrical characteristics, and behavior, such as high scalability and stability at extreme conditions such as low/high temperatures, irradiation with electromagnetic waves and high-energy particles, and fast operation are required for solving current problems in neuromorphic architectures. Electrochemical metallization (ECM)-based memristive devices are among the most relevant in this scenario owing to their low power consumption, high switching speed, showing high HRS/LRS resistance ratio in digital mode, and as well multilevel to analogue-type performance, allowing to be used in wide spectrum of applications, including as artificial neurons and/or synapses in brain-inspired hardware. Despite all the advantages and progressing industrial implementation, effects of materials selection and interactions are not sufficiently explored, and reliable design rules based on materials approach are still to be formulated by the correct choice of structures and materials combinations to ensure desired performance. In this work, we report on the effects of impurities in the copper active electrode on the electrical characteristics of Cu/Ta2O5/Pt ECM devices. The results demonstrate that Cu impurity is modulating the electrochemical behavior and switching speed due to different catalytic activity and redox reaction rates. In addition, stability and variability are improved by decreasing the number of foreign atoms. Our results provide important additional information on the factors needed to be considered for rational device design

Copy Number Variations Due to Large Genomic Deletion in X-Linked Chronic Granulomatous Disease

Mutations in genes for any of the six subunits of NADPH oxidase cause chronic granulomatous disease (CGD), but almost 2/3 of CGD cases are caused by mutations in the X-linked CYBB gene, also known as NAD (P) H oxidase 2. Approximately 260 patients with CGD have been reported in Japan, of whom 92 were shown to have mutations of the CYBB gene and 16 to have chromosomal deletions. However, there has been very little detailed analysis of the range of the deletion or close understanding of the disease based on this. We therefore analyzed genomic rearrangements in X-linked CGD using array comparative genomic hybridization analysis, revealing the extent and the types of the deletion genes. The subjects were five Japanese X-linked CGD patients estimated to have large base deletions of 1 kb or more in the CYBB gene (four male patients, one female patient) and the mothers of four of those patients. The five Japanese patients were found to range from a patient exhibiting deletions only of the CYBB gene to a female patient exhibiting an extensive DNA deletion and the DMD and CGD phenotype manifested. Of the other three patients, two exhibited CYBB, XK, and DYNLT3 gene deletions. The remaining patient exhibited both a deletion encompassing DNA subsequent to the CYBB region following intron 2 and the DYNLT3 gene and a complex copy number variation involving the insertion of an inverted duplication of a region from the centromere side of DYNLT3 into the deleted region