3,558 research outputs found
Near-field scanning microwave microscope for interline capacitance characterization of nanoelectronics interconnect
We have developed a noncontact method for measurement of the interline
capacitance in Cu/low-k interconnect. It is based on a miniature test vehicle
with net capacitance of a few femto-Farads formed by two 20-\mu m-long parallel
wires (lines) with widths and spacings the same as those of the interconnect
wires of interest. Each line is connected to a small test pad. The vehicle
impedance is measured at 4 GHz by a near-field microwave probe with 10 \mu m
probe size via capacitive coupling of the probe to the vehicle's test pads.
Full 3D finite element modeling at 4 GHz confirms that the microwave radiation
is concentrated between the two wires forming the vehicle. An analytical lumped
element model and a short/open calibration approach have been proposed to
extract the interline capacitance value from the measured data. We have
validated the technique on several test vehicles made with copper and low-k
dielectric on a 300 mm wafer. The vehicles interline spacing ranges from 0.09
to 1 \mu m and a copper line width is 0.15 \mu m. This is the first time a
near-field scanning microwave microscope has been applied to measure the lumped
element impedance of a test vehicle
Correcting Charge-Constrained Errors in the Rank-Modulation Scheme
We investigate error-correcting codes for a the
rank-modulation scheme with an application to flash memory
devices. In this scheme, a set of n cells stores information in the
permutation induced by the different charge levels of the individual
cells. The resulting scheme eliminates the need for discrete
cell levels, overcomes overshoot errors when programming cells (a
serious problem that reduces the writing speed), and mitigates the
problem of asymmetric errors. In this paper, we study the properties
of error-correcting codes for charge-constrained errors in the
rank-modulation scheme. In this error model the number of errors
corresponds to the minimal number of adjacent transpositions required
to change a given stored permutation to another erroneous
oneâa distance measure known as Kendallâs Ï-distance.We show
bounds on the size of such codes, and use metric-embedding techniques
to give constructions which translate a wealth of knowledge
of codes in the Lee metric to codes over permutations in Kendallâs
Ï-metric. Specifically, the one-error-correcting codes we construct
are at least half the ball-packing upper bound
Next Steps to Reform the Regulations Governing Offshore Oil and Gas Planning and Leasing
The Department of the Interior manages offshore oil and gas activities in federal waters. While the agency has proposed and/or enacted important improvements to the rules that govern some of those activities, it has not modernized the regulations that govern offshore oil and gas planning, lease sales, or the review and permitting of exploratory drilling. These phases of the process are overseen by the Bureau of Ocean Energy Management (BOEM), and, as was shown in our earlier publication on this topic, are ineffective and in need of modernization. In this Article, we argue that fundamental reform is necessary and highlight a series of key themes and topics that must be addressed to improve the regulatory process and promote better, more consistent management outcomes. While the Article draws on examples from frontier areasâin particular the U.S. Arctic Oceanâthe recommended changes would apply to and benefit all areas of the OCS
Estimating the spatial and temporal distribution of species richness within Sequoia and Kings Canyon National Parks.
Evidence for significant losses of species richness or biodiversity, even within protected natural areas, is mounting. Managers are increasingly being asked to monitor biodiversity, yet estimating biodiversity is often prohibitively expensive. As a cost-effective option, we estimated the spatial and temporal distribution of species richness for four taxonomic groups (birds, mammals, herpetofauna (reptiles and amphibians), and plants) within Sequoia and Kings Canyon National Parks using only existing biological studies undertaken within the Parks and the Parks' long-term wildlife observation database. We used a rarefaction approach to model species richness for the four taxonomic groups and analyzed those groups by habitat type, elevation zone, and time period. We then mapped the spatial distributions of species richness values for the four taxonomic groups, as well as total species richness, for the Parks. We also estimated changes in species richness for birds, mammals, and herpetofauna since 1980. The modeled patterns of species richness either peaked at mid elevations (mammals, plants, and total species richness) or declined consistently with increasing elevation (herpetofauna and birds). Plants reached maximum species richness values at much higher elevations than did vertebrate taxa, and non-flying mammals reached maximum species richness values at higher elevations than did birds. Alpine plant communities, including sagebrush, had higher species richness values than did subalpine plant communities located below them in elevation. These results are supported by other papers published in the scientific literature. Perhaps reflecting climate change: birds and herpetofauna displayed declines in species richness since 1980 at low and middle elevations and mammals displayed declines in species richness since 1980 at all elevations
States' Roles in Shaping High Performance Health Systems
Analyzes results from the State Health Policies Aimed at Promoting Excellent Systems survey and a review of current research on efforts to improve state healthcare systems, with a focus on coverage; quality, safety, and value; and infrastructure
The Digital Shareholder
Crowdfunding, a new Internet-based securities market, was recently authorized by federal and state law in order to create a vibrant, diverse, and inclusive system of entrepreneurial finance. But will people really send their money to strangers on the Internet in exchange for unregistered securities in speculative startups? Many are doubtful, but this Article looks to first principles and finds reason for optimism.
Well-established theory teaches that all forms of startup finance must confront and overcome three fundamental challenges: uncertainty, information asymmetry, and agency costs. This Article systematically examines this âtrio of problemsâ and potential solutions in the context of crowdfunding. It begins by considering whether known solutions used in traditional forms of entrepreneurial finance â venture capital, angel investing, and public companies â can be borrowed by crowdfunding. Unfortunately, these methods, especially the most powerful among them, will not translate well to crowdfunding.
Finding traditional solutions inert, this Article presents five novel solutions that respond directly to crowdfundingâs distinctive digital context: (1) wisdom of the crowd; (2) crowdsourced investment analysis; (3) online reputation; (4) securities-based compensation; and (5) digital monitoring. Collectively, these solutions provide a sound basis for crowdfunding to overcome the three fundamental challenges and fulfill its compelling vision
Crowdfunding Issuers in the United States
Equity crowdfunding allows startup companies to sell shares of stock, bonds or other securities to the public using online capital markets. This allows entrepreneurs to avoid the costly process of a traditional IPO. Equity crowdfunding started in America in May 2016. This article explores the types of companies that utilize equity crowdfunding, and finds that most issuers are early-stage companies; most are corporations; there is significant geographic diversity amongst the issuers, and twenty-eight percent of issuers are female-founded or female led, which is much higher than in venture capital or angel investing
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