Future semiconductor design may encounter obstacles

A group of physicists from McGill University (mcgilluniversity) in Canada have confirmed that when the wire is made up of two different metals, the current is likely to be significantly reduced, meaning that future semiconductor design may encounter obstacles.

The researchers, working with GM, the US carmaker, have discovered a surprising surge in current, and the choice of materials and component design can be a major challenge in the emerging nano-electronics sector. As the size of the semiconductor element continues to be miniaturized, future chip design engineers will need to understand how the behavior pattern of the charge changes when the diameter of the wire is limited to just a few atoms wide.

Petergrutter, a professor of physics at McGill University, said that when the chip line size was gradually scaled to the atomic level, the current impedance would no longer increase with the miniature of the component at a constant rate; Show the counter-intuitive effects of quantum mechanics (Counterintuitiveeffect).

"This phenomenon can be likened to a rubber hose;" Grutter said: "If you keep the water pressure constant, when you reduce the diameter of the pipe, the amount of water will be less, and if you reduce the size of the water pipe to the size of the straw, diameter only 2~3 atoms wide, out?" The amount of water will no longer shrink in proportion to the cross-sectional size of the pipe, and its quantification (jump) will change. ”

Grutter and colleagues at McGill University and GM researchers wrote this "quantum quantumweirdness" in a paper published in the National Academy of Sciences Bulletin (proceedingsofthenationalacademyofsciences); The team studied a kind of small gold and tungsten (tungsten) alloy contacts, which are now often combined in semiconductor components as conductors of different 0 components in a connecting device.

In Grutter's lab, the researchers used advanced microscopy techniques to capture the images of tungsten probes and gold surfaces with atomic and precision, and to combine the two metals in a controlled precision (precisely-controlled) method, and they found that the current of the alloy contact was much lower than expected.

The research team at McGill University, in collaboration with scientists from the GM Research and Development Center, YUEQI the atomic structural mechanical model of the alloy contacts, proving that the differences in the electronic structure between the two metals can lead to a four times-fold reduction in current, even if the two materials achieve the Perfect interface (Perfectinterface).

In addition, researchers have found that the crystal defects (crystaldefect) that bind the two metal materials--which are normally perfectly aligned with the wrong atoms--are a further cause of the current drop.

McGill University student Tillhagedorn using field ion microscopy (Fieldionmicroscope)

"The amount of current we observe is 10 times times higher than most experts expect," he said. "Grutter says their findings suggest more research is needed in the future to overcome such problems, perhaps through material choices or other processing techniques:" The first step to finding a solution is to be aware of such problems, and we are the first to confirm that this is a big problem for the Nano electronic system. " ”