Low-power, 10-Gbps 1.5-Vpp differential CMOS driver for a silicon electro-optic ring modulator

We present a novel driver circuit enabling electro-optic modulation with high extinction ratio from a co-designed silicon ring modulator. The driver circuit provides an asymmetric differential output at 10Gbps with a voltage swing up to 1.5V(pp) from a single 1.0V supply, maximizing the resonance-wavelength shift of depletion-type ring modulators while avoiding carrier injection. A test chip containing 4 reconfigurable driver circuits was fabricated in 40nm CMOS technology. The measured energy consumption for driving a 100fF capacitive load at 10Gbps was as low as 125fJ/bit and 220fJ/bit at 1V(pp) and 1.5V(pp) respectively. After flip-chip integration with ring modulators on a silicon-photonics chip, the power consumption was measured to be 210fJ/bit and 350fJ/bit respectively

COVID-19 symptoms at hospital admission vary with age and sex: results from the ISARIC prospective multinational observational study

Background: The ISARIC prospective multinational observational study is the largest cohort of hospitalized patients with COVID-19. We present relationships of age, sex, and nationality to presenting symptoms. Methods: International, prospective observational study of 60 109 hospitalized symptomatic patients with laboratory-confirmed COVID-19 recruited from 43 countries between 30 January and 3 August 2020. Logistic regression was performed to evaluate relationships of age and sex to published COVID-19 case definitions and the most commonly reported symptoms. Results: ‘Typical’ symptoms of fever (69%), cough (68%) and shortness of breath (66%) were the most commonly reported. 92% of patients experienced at least one of these. Prevalence of typical symptoms was greatest in 30- to 60-year-olds (respectively 80, 79, 69%; at least one 95%). They were reported less frequently in children (≤ 18 years: 69, 48, 23; 85%), older adults (≥ 70 years: 61, 62, 65; 90%), and women (66, 66, 64; 90%; vs. men 71, 70, 67; 93%, each P < 0.001). The most common atypical presentations under 60 years of age were nausea and vomiting and abdominal pain, and over 60 years was confusion. Regression models showed significant differences in symptoms with sex, age and country. Interpretation: This international collaboration has allowed us to report reliable symptom data from the largest cohort of patients admitted to hospital with COVID-19. Adults over 60 and children admitted to hospital with COVID-19 are less likely to present with typical symptoms. Nausea and vomiting are common atypical presentations under 30 years. Confusion is a frequent atypical presentation of COVID-19 in adults over 60 years. Women are less likely to experience typical symptoms than men

Design strategy for the integration of DSA vias in sub-7 nm circuits

Invited talkstatus: publishe

Two-step interconnect testing of semiconductor dies

\u3cp\u3eA method is provided for testing an interconnect (32) in a semiconductor die (30), the semiconductor die (30) having at its surface a plurality of electrical contact elements (Pad A, Pad B, Pad X, Pad Y), and comprising at least an interconnect-under-test (32) between a first electrical contact element (Pad A) and a second electrical contact element (Pad B), there being an electrical component (C) electrically coupled between the interconnect-under-test (32) and at least one third electrical contact element (Pad X, Pad Y). The method comprises testing a first signal path in the semiconductor die (30) for manufacturing defects, the first signal path comprising a first part of the interconnect-under-test (32) and a first deviation path from the interconnect-under-test (32) over the electrical component (C) to a third electrical contact element (Pad X), thus obtaining first test results; and testing a second signal path in the semiconductor die (30) for manufacturing defects, the second signal path comprising a second part of the interconnect-under-test (32) and a second deviation path from the interconnect-under-test (32) over the electrical component (C) to a third electrical contact element (Pad Y), thus obtaining second test results. The first and the second part of the interconnect-under-test together form the interconnect-under-test (32).\u3c/p\u3

Two-step interconnect testing of semiconductor dies

\u3cp\u3eThe present invention relates generally to testing of interconnects in a semiconductor die, and more particularly to testing of semiconductor chips that are three-dimensionally stacked via an interposer. In one aspect, a method for testing an interconnect in a semiconductor die comprises providing the semiconductor die, which includes a plurality of electrical contact elements formed at one or more surfaces of the semiconductor die, at least one interconnect-under-test disposed between a first electrical contact element and a second electrical contact element, and an electrical component electrically coupled between the interconnect-under-test and at least one third electrical contact element.\u3c/p\u3

Clonidine-induced growth hormone secretion in elderly patients with senile dementia of the alzheimer type and major depressive disorder

This study was undertaken to assess the value of growth hormone (GH) response to clonidine as a tool in the differential diagnosis between depression and dementia. This response is known to be blunted in depression, and neurochemical changes observed in senile dementia of the Alzheimer type (SDAT) could lead to an up-regulation of GH secretion. No difference was observed between GH response in depressed and demented patients. Together with studies on GH basal secretion in Alzheimer's disease, this findings suggests that the final consequence of SDAT-related changes is an accentuation of the effects of aging on GH reactivity. © 1989.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Design strategy for layout of Sub-Resolution Directed Self-Assembly Assist Features (SDRAFs)

In the pursuit of alternatives to optical lithography, block copolymer directed self-assembly (DSA) has emerged as a low-cost, high-throughput option. DSA uses small topographical templates to contain the block copolymer and create small clusters of holes useful for patterning vias [1]. However, issues of defectivity have hampered DSA' s viability for large-scale patterning. Recent studies have shown polymer fill level to be a crucial factor in defectivity, as template overfill can result in malformed DSA structures [2]. The inherent density variations in via layouts, though, make regions of overfilled templates nearly inevitable, as templates in less dense regions will contain more polymer. For this reason, we develop a method to integrate sub-DSA resolution assist features (SDRAFs) into DSA template layouts. The SDRAFs divert excess polymer from the overfilled main templates but are themselves too small to form transferrable DSA patterns [2]. Thus, we can populate low-density regions with SDRAFs to make a layout more uniformly dense. To do this, we use SDRAFs with a set of lithography-based design rules dictating the minimum pitch and resist thickness between features (95 nm and 45 nm for 193i, respectively). The SDRAF CD is also chosen to be as large as possible without forming a transferrable DSA pattern, setting it at 40 nm for an L0 = 40 nm polymer and a PS wetting flow. With these rules, we set a flow for the assignment of each SDRAF according to the calculated density of templates in each block. We demonstrate the process on a 2.5 x 2.5 um section from V23 (the via layer connecting metals 2 and 3) of a routed N7 Cortex-M0 processor scaled to a 24 nm via layout grid. We first overlay the template layout with a grid of SDRAFs spaced at 96 nm, allowing the SDRAFs to align with the via grid. We then remove the SDRAFs that violate the minimum resist or pitch rules and assess the density result. This is done by dividing the layout into blocks and calculating the percentage of area occupied by the main and assist templates in the blocks, using prior experimental data for template area [3]. The size of the blocks is set to the length over which the polymer reflows during the thermal anneal [4], assumed here to be about 500 nm. Finally, the SDRAF grid is shifted vertically and horizontally in increments of the via grid (24 nm) to achieve different density results, as each shift causes different SDRAFs to be in violation. We can then choose the shift that minimizes the density variation across the blocks as the final layout. In our test case, we found that the density range of the blocks changed from 2.8-8.6% to 10.9-12.9% post-SDRAF assignment. Here, the polymer film thickness can be adjusted to accommodate the higher overall density and the narrowed density range shows promise to reduce template overfill. Future work will incorporate methods of improving the layout's PV band to create an SDRAF design strategy that is more DSA- and lithography-friendly. [1] H. Yi et al., Adv. Mater 24, 23 (2012). [2] H. Yi et al., Proc. SPIE 9423, 1F (2015). [3] J. Doise et al., J. Vac. Sci. Technol. B 33, 6 (2015). [4] H. Yi et al., Proc. SPIE 9323, 2A (2015).status: publishe

Ultra wide-band body area channel model

Using wireless sensors placed on a person to continuously monitor health information is a promising new application. However, there are currently no models describing the radio channel around the human body making it difficult to design a suitable communication system. To address this problem, we have simulated electromagnetic wave propagation around the body and incorporated these results into a simple model. We then compared this model with measurements taken around the human torso and with previous studies in the literature. This paper proposes a simple statistical channel model useful for evaluating both UWB and (after resampling) narrow-band body area communication systems. © 2005 IEEE.SCOPUS: cp.p24144492988info:eu-repo/semantics/publishe