Self-assembling silicon circuits

Paul Raven @ 17-03-2010

Photolithography is running up against its limitations, as logic circuits become so small that the wavelength of light itself is too large to mask the patterns accurately. MIT boffins reckon they have a solution, though: self-assembling semiconductor circuits [via NextBigFuture].

Berggren and Ross’ approach is to use electron-beam lithography sparingly, to create patterns of tiny posts on a silicon chip. They then deposit specially designed polymers — molecules in which smaller, repeating molecular units are linked into long chains — on the chip. The polymers spontaneously hitch up to the posts and arrange themselves into useful patterns.

The trick is that the polymers are “copolymers,” meaning they’re made of two different types of polymer. Berggren compares a copolymer molecule to the characters played by Robert De Niro and Charles Grodin in the movie Midnight Run, a bounty hunter and a white-collar criminal who are handcuffed together but can’t stand each other. Ross prefers a homelier analogy: “You can think of it like a piece of spaghetti joined to a piece of tagliatelle,” she says. “These two chains don’t like to mix. So given the choice, all the spaghetti ends would go here, and all the tagliatelle ends would go there, but they can’t, because they’re joined together.” In their attempts to segregate themselves, the different types of polymer chain arrange themselves into predictable patterns.

Clever stuff, though still very much in the developmental stages. Maybe another new lease of life for Moore’s Law?

Swarming to it

Tom James @ 28-08-2009

iswarm4One of my favourite[1] plausible science fictional tropes is that of tiny robotic insects. The latest step towards their instantiation has been taken by researchers in Sweden, Spain, Germany, Italy, and Switzerland as they put forward their conception of how swarms of mass-produced robotic fleas could be used for surveillance, cleaning, and medical applications:

The technique involves integrating an entire robot – with communication, locomotion, energy storage, and electronics – in different modules on a single circuit board.

In the past, the single-chip robot concept has presented significant limitations in design and manufacturing. However, instead of using solder to mount electrical components on a printed circuit board as in the conventional method, the researchers use conductive adhesive to attach the components to a double-sided flexible printed circuit board using surface mount technology.

The circuit board is then folded to create a three-dimensional robot.

I can imagine that once this sort of technology matures it will herald a profound change for society. An Orwellian Panopticon where everyone and everything is traced and followed and tracked will become a practicable possibility. Privacy will become one of the most valuable commodities on the planet, with the richest and most powerful people cowering in enclaves sterilized against micro-invaders.

[1]: In that I enjoy them as part of a story and am not entirely ambivalent to their actuality.

[from Physorg][image from Physorg]

First artificial organelle

Tom James @ 05-08-2009

artificial_organelleResearchers have developed an artificial cellular organelle to aid in the development of artificial synthesis the life-saving anti-clotting drug heparin:

Scientists have been working to create a synthetic version of the medication, because the current production method leaves it susceptible to contamination–in 2008, such an incident was responsible for killing scores of people. But the drug has proven incredibly difficult to create in a lab.

Much of the mystery of heparin production stems from the site of its natural synthesis: a cellular organelle called the Golgi apparatus, which processes and packages proteins for transport out of the cell, decorating the proteins with sugars to make glycoproteins. Precisely how it does this has eluded generations of scientists.

To better understand what was going on inside the Golgi, Linhardt and his colleagues decided to create their own version. The result: the first known artificial cell organelle, a small microfluidics chip that mimics some of the Golgi’s actions.

As well as the utility of being able to produce drugs in this way, it is impressive the degree of control that can be exerted over the matter:

The digital device allows the researchers to control the movement of a single microscopic droplet while they add enzymes and sugars, split droplets apart, and slowly build a molecule chain like heparin.

[from Technology Review, via KurzwailAI][image from Technology Review]

Top new computer chip material

Tom James @ 15-06-2009

electron_band_bismuth_tellurideResearcher at the Stanford Institute for Materials & Energy Science have developed a new substance for making computer chips that allows electrons to flow without any loss of energy at room temperatures and can be made using existing chip-making technologies:

Physicists Yulin Chen, Zhi-Xun Shen and their colleagues tested the behavior of electrons in the compound bismuth telluride. The results, published online June 11 in Science Express, show a clear signature of what is called a topological insulator, a material that enables the free flow of electrons across its surface with no loss of energy

This is pretty amazing in and of itself, but is not quite a superconductor:

Topological insulators aren’t conventional superconductors nor fodder for super-efficient power lines, as they can only carry small currents, but they could pave the way for a paradigm shift in microchip development. “This could lead to new applications of spintronics, or using the electron spin to carry information,”

[from Physorg][image via Physorg from Yulin Chen and Z. X. Shen]

How will the earliest nanofactories emerge?

Tom James @ 04-06-2009

dimensionsJ Storrs Hall of the Foresight institute comments on what the earliest nanofactories will be like, and Michael Anissimov responds:

If nanofactories work at all, they will be very powerful. A nanofactory would be a very complicated, “huge” thing. The Center for Responsible Nanotechnology compares the complexity of a molecular assembler to that of a Space Shuttle. I think the analogy would be apt for a nanofactory as well. We are talking about a miniature factory with more moving parts and individual computers than a typical 100 million-dollar modern factory today. Difficulties with the basic technology will manifest themselves in the pre-nanofactory stage, working with individual assemblers or small ensembles of assemblers. If you’ve made it all the way to nanofactory-level MNT, you’ve already jumped the primary technological hurdles.

A point of disagreement between Anissimov and Hall is the precise definiton of “nanofactory.” Is it simply a general term for a device that can create many other things including a copy of itself, or it is a specific desktop-scale universal assembler?

Assuming the latter definition, Anissimov argues that widespread adoption of desktop nanofactories will happen much more rapidly than that of personal computers because:

There are simply too many moving parts for micromanagement to be possible — either the “code-level” operations are automated or they haven’t been established yet.

Either they work or they don’t. The smallest replicating unit is equivalent to the transistor in a personal computer – to the user it is expected to behave as a black box that performs a specific function – and if it fails to there is not much the user can do about it (if a transistor fails on a microchip can it even be repaired?).

The appropriate analogy is therefore between computers and nanofactories is between the existence of nanofactories and the existence of microchips. Microchips have found their way all over the place…

If Anissimov is right then it raises the interesting possibility that mature, desktop-scale nanofabrication may achieve widespread consumer adoption over a startlingly short period, given the ability of the machine to make copies of itself and the fact if it fulfils its basic function then it can become incredibly useful to many people very quickly.

[via Next Big Future][image from jurvetson on flickr]

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