Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Purdue engineers create model for testing transistor reliability

01.12.2004


Researchers at Purdue University have created a "unified model" for predicting the reliability of new designs for silicon transistors – a potential tool that industry could use to save tens of millions of dollars annually in testing costs.



The model is the first method that can be used to simultaneously evaluate the reliability of two types of transistors essential for so-called CMOS computer chips, the most common type of integrated circuits in use today. The two types of transistors degrade differently over time, and the model is able to relate these two different classes of degradation simultaneously. "It is the first single tool for accurately predicting how new designs for both types of transistors will degrade over time," said Ashraf Alam, a professor of electrical and computer engineering at Purdue.

The degradation revolves around bonds between atoms of hydrogen and silicon and hydrogen and silicon dioxide. Specifically, the mathematical model enables researchers to see the rates at which these hydrogen bonds in the two types of transistors will break over time. The breaking bonds are directly related to a transistor’s long-term reliability. Because hydrogen bonds break differently in the two types of transistors, separate models have been required in conventional testing for new designs. "This testing requires a huge amount of resources, costing companies millions of dollars annually," Alam said. "If you could explain both within the same framework, then you could cut down significantly on the number of measurements required to characterize the performance of the transistors."


Findings about the new model will be detailed in a research paper to be presented Dec. 13 during the 50th annual IEEE International Electron Devices Meeting, sponsored by the Institute of Electrical and Electronics Engineers, in San Francisco. The paper was written by Alam and Purdue engineering doctoral student Haldun Kufluoglu. "A major goal of reliability models is to predict how well electronic components will work perhaps 10 years after they are manufactured," Alam said. "In order to do that, you first need to be able to understand the devices very well so that you can extrapolate how reliable they will be in the future. "You need to understand the details of how the device operates and how various materials behave over time so that you can see how the different chemical bonds will gradually break and how the integrated circuit will gradually lose its function. For a multibillion dollar electronics industry, that knowledge has huge implications."

Bonds between silicon and hydrogen are critical to the proper performance of transistors.

"Even for the tiniest transistor today, there are perhaps thousands of these silicon-hydrogen bonds," Kufluoglu said. "These bonds gradually break. Initially, it doesn’t matter because there are so many of these bonds. But over a period of time, when lots of them begin to break, the different transistors within an integrated circuit start getting out of synch."

CMOS, or complementary metal oxide semiconductor chips, are made of PMOS and NMOS transistors, both of which are essential for CMOS integrated circuits. Integrated circuits inside computers contain equal parts of PMOS (positive polarity) and NMOS (negative polarity) transistors. "The important point is that the mechanisms by which the silicon-hydrogen bonds break are different for these two types of transistors," Alam said. "And that is why, for the past 30 years, we have treated these processes with separate models, because we didn’t know how to put them in a common framework, or a common language, mathematically." The paper describes the underlying mechanism for the breaking bonds in the two types of transistors, he said.

The model not only describes the rate at which the silicon-hydrogen bonds break, but also how they "repair" themselves. "If you don’t use your computer for some period of time, say 24 hours, gradually the hydrogen that went away will diffuse back and combine with silicon to make the bond whole again," Alam said. "Researchers already knew the rates at which the broken bonds are made whole again, but because these rates are much different in the PMOS and NMOS transistors, there was no model that could explain both simultaneously." The bonds repair themselves much faster in PMOS transistors than in NMOS transistors, he said.

The new model will likely be particularly useful to test the reliability of designs for silicon-based chips that use nanotechnology to create smaller and more compact transistors than exist in today’s integrated circuits, Alam said.

Writer: Emil Venere, (765) 494-4709, venere@purdue.edu

Sources: Ashraf Alam, (765) 494-5988, alam@ecn.purdue.edu

Haldun Kufluoglu, (765) 494-9034, haldun@purdue.edu

Purdue News Service: (765) 494-2096; purduenews@purdue.edu

Emil Venere | EurekAlert!
Further information:
http://www.purdue.edu

More articles from Power and Electrical Engineering:

nachricht Waste from paper and pulp industry supplies raw material for development of new redox flow batteries
12.10.2017 | Johannes Gutenberg-Universität Mainz

nachricht Low-cost battery from waste graphite
11.10.2017 | Empa - Eidgenössische Materialprüfungs- und Forschungsanstalt

All articles from Power and Electrical Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

 
Latest News

Terahertz spectroscopy goes nano

20.10.2017 | Information Technology

Strange but true: Turning a material upside down can sometimes make it softer

20.10.2017 | Materials Sciences

NRL clarifies valley polarization for electronic and optoelectronic technologies

20.10.2017 | Interdisciplinary Research

VideoLinks
B2B-VideoLinks
More VideoLinks >>>