Tetsu Tanaka

Bio: Tetsu Tanaka is an academic researcher from Tohoku University. The author has contributed to research in topics: Wafer & Chip. The author has an hindex of 38, co-authored 406 publications receiving 10375 citations. Previous affiliations of Tetsu Tanaka include NTT DoCoMo & Tokyo Medical and Dental University.

A novel SPRAM (SPin-transfer torque RAM)-based reconfigurable logic block for 3D-stacked reconfigurable spin processor

Abstract: A novel reconfigurable logic block with SPRAM (spin-transfer torque RAM) is demonstrated. Magnetic elements of 50 times 200 nm2 in area and CMOS logic are fully integrated. Laboratory experimental results show that our reconfigurable logic block achieves 25 MHz read out operation with the magnetic resistance of 1.62 kOmega (parallel) and the MR ratio is 91.7 %.

Impact of Cu diffusion from Cu through-silicon via (TSV) on device reliability in 3-D LSIs evaluated by transient capacitance measurement

Abstract: The influence of Cu contamination from Cu through-silicon via (TSV) on device reliability in the 3-D LSI was electrically evaluated by capacitance-time (C-t) measurement. The Cu/Ta gate trench capacitors with two types of Ta barrier layers of 10-nm and 100-nm thicknesses (at the wafer surface) were fabricated. The C-t curves of the trench capacitors with 10-nm thick Ta layer were severely degraded even after the initial annealing for 5min. It means that Cu atoms diffuse into the active area from the Cu TSV through scallop portions with extremely thin Ta layer in TSVs, and consequently, the generation lifetime of minority carrier is significantly reduced. Meanwhile, the C-t curves of the trench capacitors with 100-nm thick Ta layer exhibit no change after annealing up to 60min at 300°C, but show significant degradation after the initial annealing for 5min at 400°C. The C-t analysis is a useful method to electrically characterize the influence of Cu contamination from the Cu TSV on device reliability in fabricated LSI wafers.

Through Silicon photonic via (TSPV) with Si core for low loss and high-speed data transmission in opto-electronic 3-D LSI

Abstract: To realize very high performance computing system, we have proposed a novel opto-electronic 3-D LSI in which both electrical and optical devices are integrated. For realizing such opto-electronic 3-D LSI, through Si photonic via (TSPV) is indispensable for vertical light transmission. In this work, we fabricated the TSPV comprising Si core and epoxy cladding. We measured near field patterns (NFP) of laser light passed through the TSPV to evaluate its light confinement effect. From the results of NFP measurement, we confirmed that the laser light was successfully confined and propagated in the Si core region of the TSPV. We successfully developed a fabrication process to form both the TSPV and TSV simultaneously. The size of the fabricated TSPV and TSV was 20μm×20μm and 16μm×16μm, respectively.

A parallel ADC for high-speed CMOS image processing system with 3D structure

Abstract: In this paper, we describe the fundamental study of a parallel signal processing circuit, which includes a pixel circuit and a parallel analog-to-digital converter (ADC) with hierarchical correlated double sampling (CDS). To realize high speed image capturing sensor, we have proposed a block-parallel signal processing with three-dimensional (3D) structure. Using 3D structure, the different function layers are stacked vertically and interconnected electrically by through-Si vias (TSVs), which can improve sensor performance and signal band width. On the other hand, the fixed pattern noise (FPN), caused by the circuit device variation, becomes a critical challenge. Experiments on the fabricated pixel circuit have been implemented in a single-layer (two-dimensional) 0.18-µm CMOS image sensor technology. With the analog CDS, the FPN of pixel circuit is reduced by 8.6%. To eliminate the FPN of parallel ADC, a digital CDS technique is implemented. The proposed ADC with digital CDS is designed in a two-dimensional 0.18-µm CMOS technology. The ADC design, including an 8-bit memory, a 6-bit memory, a subtraction circuit, and a comparator, occupies 100×100µm2 area and 0.9mW with supply voltage 1.8 V and 1 MS/s conversion rate. The functional simulation and measurement results confirm that our techniques can effectively reduce fixed pattern noise.

Direct measurement of V/sub th/ fluctuation caused by impurity positioning

Abstract: This paper studies a local fluctuation of channel impurity on the source edge. Our direct measurement successfully separates the local (intra-FET) and global (inter-FET) factors. The quite local region (/spl Lt/L/sub eff//spl times/W/sub eff/) significantly affects V/sub th/ distribution in a high V/sub d/, which exceeds the global factor in the smallest MOSFETs. The local fluctuation inevitably affects MOSFETs in SRAM cells even though global fluctuation is reduced by process optimization.

Deciphering the biology of Mycobacterium tuberculosis from the complete genome sequence

Abstract: Countless millions of people have died from tuberculosis, a chronic infectious disease caused by the tubercle bacillus. The complete genome sequence of the best-characterized strain of Mycobacterium tuberculosis, H37Rv, has been determined and analysed in order to improve our understanding of the biology of this slow-growing pathogen and to help the conception of new prophylactic and therapeutic interventions. The genome comprises 4,411,529 base pairs, contains around 4,000 genes, and has a very high guanine + cytosine content that is reflected in the biased amino-acid content of the proteins. M. tuberculosis differs radically from other bacteria in that a very large portion of its coding capacity is devoted to the production of enzymes involved in lipogenesis and lipolysis, and to two new families of glycine-rich proteins with a repetitive structure that may represent a source of antigenic variation.

Antiinflammatory Therapy with Canakinumab for Atherosclerotic Disease

Abstract: BackgroundExperimental and clinical data suggest that reducing inflammation without affecting lipid levels may reduce the risk of cardiovascular disease. Yet, the inflammatory hypothesis of atherothrombosis has remained unproved. MethodsWe conducted a randomized, double-blind trial of canakinumab, a therapeutic monoclonal antibody targeting interleukin-1β, involving 10,061 patients with previous myocardial infarction and a high-sensitivity C-reactive protein level of 2 mg or more per liter. The trial compared three doses of canakinumab (50 mg, 150 mg, and 300 mg, administered subcutaneously every 3 months) with placebo. The primary efficacy end point was nonfatal myocardial infarction, nonfatal stroke, or cardiovascular death. ResultsAt 48 months, the median reduction from baseline in the high-sensitivity C-reactive protein level was 26 percentage points greater in the group that received the 50-mg dose of canakinumab, 37 percentage points greater in the 150-mg group, and 41 percentage points greater in t...

Complete genome sequence of Pseudomonas aeruginosa PAO1, an opportunistic pathogen.

Abstract: Pseudomonas aeruginosa is a ubiquitous environmental bacterium that is one of the top three causes of opportunistic human infections. A major factor in its prominence as a pathogen is its intrinsic resistance to antibiotics and disinfectants. Here we report the complete sequence of P. aeruginosa strain PAO1. At 6.3 million base pairs, this is the largest bacterial genome sequenced, and the sequence provides insights into the basis of the versatility and intrinsic drug resistance of P. aeruginosa. Consistent with its larger genome size and environmental adaptability, P. aeruginosa contains the highest proportion of regulatory genes observed for a bacterial genome and a large number of genes involved in the catabolism, transport and efflux of organic compounds as well as four potential chemotaxis systems. We propose that the size and complexity of the P. aeruginosa genome reflect an evolutionary adaptation permitting it to thrive in diverse environments and resist the effects of a variety of antimicrobial substances.