5 tech breakthroughs: Chip-level advances that may change computing

Imagine a world with electronic devices that can power themselves, music players that hold a lifetime of songs, self-healing batteries, and chips that can change abilities on the fly. Based on what's going on in America's research laboratories, these things are not only possible, but likely.

 "The next five years will be a very exciting time for electronics," says David Seiler, chief of the semiconductor electronics division at the Department of Commerce's National Institute of Standards and Technology (NIST) in Gaithersburg, Md. "There will be lots of things that today seem like far-out fantasy but will start to be commonplace."

In this two-part series, we'll take you on a tour of what could be the future of electronics. Some of these ideas may sound fantastic, others simply a long-overdue dose of common sense, but the common thread is that they have all been demonstrated in the lab and have the potential to become commercially available products in the next five years or so.

Today's story focuses on chip-level advances, from processors that transmit data via lasers instead of wires to circuits made with new materials that leave conventional silicon ones in the dust. These technologies could be the building blocks for a plethora of new and innovative products, some of which we can't even conceive of today.

1) Chips without wires: The laser connection:

An up-close look at any microprocessor reveals millions of tiny wires going every which way to connect its active elements. Go below the surface, and there can be more than five times as many wires. Jurgen Michel, a researcher at MIT's Microphotonics Center in Cambridge, Mass., wants to replace all those wires with flashing germanium (Ge) lasers that transmit data via infrared light.

"As processors get more cores and components," explains Michel, "the interconnecting wires become clogged with data and are the weak link. We're using photons, rather than electrons, to do it better."

Capable of moving data at, well, the speed of light, a Ge laser can transmit bits and bytes 100 times faster than electricity moving through wires can, which means the critical connections between the chip's processing cores and its memory, for example, won't hold the rest of the device back. Just as fiber-optic communications made phone calls more efficient a generation ago, using lasers inside chips could put computing into overdrive.

The best part is that MIT's system doesn't require tiny fiber cables buried inside each processor. Instead, the chip is crisscrossed with a series of subterranean tunnels and caverns to transmit the pulses of light; tiny mirrors and sensors relay and interpret the data.

This mixing of traditional silicon electronics with optical components -- a practice known as silicon photonics -- can make computers greener as well. That's because lasers use less power than the wires they replace and give off less heat that needs to be cooled.

"Optoelectronics is a holy grail," says Seiler. "It can broaden electronics and is a great way to cut power use because you don't have all those wires acting like space heaters."

In February 2010, Michel and his collaborators, Lionel Kimerling and Jifeng Liu, successfully created and tested a functioning circuit that incorporates Ge laser data transfers. The chip hit speeds of over a terabit per second, or two orders of magnitude faster than today's best chips with wired connectors can do.

The chip is manufactured using current semiconductor processing techniques with some small additions, so Michel thinks that the transition to laser-based connections can happen over the next five years. If further tests are successful, MIT says it will license the process; this type of chip could become available around 2015.

The need has never been greater. By 2015, it's likely that there will be computer chips with up to 64 independent processing cores, each working simultaneously. "Connecting them with wires is a dead end," Michel says. "Using a germanium laser to connect them has huge potential and a big payoff."

2) Novel circuits: Memristors

If your MP3 player is filling up with tunes but you feel like a cultural murderer every time you delete a song, memristor technology might be arriving just in time.

The first fundamentally new electronic component to appear since silicon transistors came on the scene in the 1950s, the memristor presents a faster, more durable and potentially much cheaper alternative to flash memory. And with about twice the capacity of flash chips, there's plenty of room for everything from Leonard Bernstein to Lady Gaga.

"If we were redesigning computer technology today, we'd use memristor memory," says R. Stanley Williams, senior researcher and head of the Quantum Science Research (QSR) group at HP Labs in Palo Alto, Calif. "It's the fundamental structure for the future of electronics."

The memristor -- basically a resistor with memory -- was first posited in 1971 by University of California, Berkeley, professor Leon Chua, but HP Labs' memristor prototypes weren't publicly demonstrated until 2008.

To build its memristors, HP uses alternating layers of titanium dioxide and platinum; under an electron microscope they look like a series of long parallel ridges. Below the surface is a similar setup at a right angle, producing a grid-like array.

 "Think of it as a series of cubes that are 2 to 3 nanometers (nm) on a side," says Williams. (A nanometer is one-billionth of a meter, roughly one ten-thousandth the thickness of a human hair.)

The key is that any two adjacent wires can be connected with an electrical switch beneath the surface, creating a memory cell. By adjusting the voltage applied to the cubes, scientists can open and close tiny electronic switches, storing data like traditional flash memory chips.

Called ReRAM, for resistive random access memory, these chips can store roughly twice the data as flash chips but are more than 1,000 times faster than flash memory and could last for millions of rewrite cycles, compared with the 100,000 that flash memory is certified for. The bonus is that ReRAM's read and write speeds are comparable, while flash takes a lot longer to write data than to read it.

HP and South Korea's Hynix have teamed up to mass-produce ReRAM chips that could be used in a variety of small devices, such as media players that can hold terabytes of songs, videos and e-books. They expect to see the first products on the market sometime in 2013.

ReRAM can also replace dynamic RAM in computers. Because it's nonvolatile, ReRAM won't lose its contents when the system is turned off or loses power, as DRAM does. In fact, Williams thinks it could lead to an era of instant-on computing. Even when today's devices are merely put to sleep instead of being fully shut down, it takes anywhere from a few seconds to a minute for them to access stored data upon awakening. But with ReRAM devices, you'd be able to pick up where you left off instantaneously.

3) Changeable chips: Programmable layers

From the fastest processor to the smallest memory module, just about every chip used in electronics today has one thing in common: Its active elements reside in the top 1% to 2% of the silicon material it's made of.

That will change over the next few years as chip makers go vertical to squeeze in more and more components. Some vendors, such as Intel, have resorted to gluing completed chips together, while University of Rochester researchers have designed and built 3-D circuits layer by layer internally. Both approaches are enormously complicated and expensive, observes IBM's Guha.

But what if you could trick the circuit into rearranging itself on demand so that it only appeared to other components to have several layers of active elements? That's the idea behind Tabula's Spacetime technology and its ABAX chip design.

 Rather than having several layers of hardwired components that are permanently etched into silicon and never change, ABAX uses reprogrammable circuits that can change their abilities on demand. Its current products deliver the equivalent of up to eight different chip layers that can be changed faster than the blink of an eye.

"Think of it as like a department store with eight floors," says Steve Tieg, Tabula's president and chief technology officer. "You'd take an elevator to go between floors to shop for different items." But rather than having eight different physical floors, each with its own internal arrangement and assortment of goods, Tabula has figured out a way to have a single layer (or floor) that reconfigures itself as needed.

4) From soot to circuits: Graphene

For the past 45 years, almost like clockwork, the number of transistors on a state-of-the-art silicon computer chip has roughly doubled every two years, making Moore's Law as reliable as the law of gravity. As the active elements on a chip have gotten smaller and cheaper to make, more of them could be shoehorned into devices of increasing complexity, ability and power -- all at roughly the same cost as the previous generation of products.

This embarrassment of digital riches may at last be heading toward a dead end. Scientists trying to stuff ever more transistors onto a silicon chip are having trouble reliably making active elements smaller than the current best of 14 nm -- roughly double the size of a hemoglobin molecule in blood or about one-thousandth the size of a grain of talcum powder.

 A substance called graphene could breathe new life into Moore's Law by augmenting silicon technology. Made from nothing more glamorous than soot, graphene is an atom-thick layer of carbon atoms arranged in a hexagonal pattern. Under an electron microscope, graphene looks like a cross between chicken wire and a honeycomb.

"It not only looks strange but has incredible properties," says Walt de Heer at his nanoscience lab at the Georgia Institute of Technology. "Graphene is a wonderful material to make electronics out of," he says. "It's fast, doesn't use a lot of power and can be made with very small features. It outperforms silicon and does things silicon can't. It could be the future of electronics."

5) Printed circuits: Chips on the cheap

Standard semiconductor processing involves a series of intricate steps that need to be carried out in an expensive clean room that's free of electronics-destroying dust and contaminants. But Xerox is working on a cheaper and easier way to make electronics by printing circuits on a plastic sheet. The process uses equipment that might cost hundreds of thousands of dollars, not the billions needed for traditional chip-making plants like the one Intel recently broke ground for in Chandler, Ariz.

"Conventional electronics are fast, small and expensive," observes Jennifer Ernst, formerly director of business development at Xerox's PARC research lab in Palo Alto, California. By printing them directly on plastic, however, PARC is making electronics that are "slow, big and cheap," says Ernst, now a vice president at Thin Film Electronics.

PARC's design prints circuits directly on the base material in a process that's often only slightly more involved than printing a mailing label. It requires some special materials, like silver ink, but these devices can be printed on flexible polyethylene sheets rather than on brittle silicon. In fact, the results probably shouldn't even be called chips anymore.

By adapting a variety of printing techniques, including ink-jetting, stamping and silk screening, PARC has made amplifiers, batteries and switches for a fraction of what it costs to manufacture them the traditional way. The company recently succeeded in making a 20-bit memory and controller circuit this way, and will start selling it next year. It's a drop in the digital bucket compared with megabit flash and DRAM chips, but it's a start.

Another interesting printed-circuit project is the blast detection sensor tape that PARC is developing for the U.S. Defense Advanced Research Projects Agency (DARPA). It's made by printing circuits on a flexible tape that can be pressed onto a soldier's helmet. With a flexible film battery on the back, the sensors measure the pressure (up to 100 psi), acceleration (up to 1,000 Gs), sound levels (up to 175 decibels) and light (up to 400 lux) experienced in battlefield conditions.

After a week on the front line, the soldier tears the tape off the helmet and sends it to a lab, where the data is downloaded and analyzed so that doctors can see if the soldier is in danger of a debilitating brain injury. "It replaces a $7 sensor, costs less than $1 and performs just as well," says Ernst.

On the downside, printed circuits will likely never catch up to silicon in terms of speed or the ability to put billions of transistors on something the size of a fingernail. But there are lots of places where cost counts for more than speed. As early as 2012, printed devices should start showing up in toys and games that incorporate rudimentary computing, like synthetic voices, as well as in car seat sensors for controlling the deployment of air bags in an accident. (Printed circuits are slow compared to traditional silicon electronics, but still fast enough to for air bag deployment.)

 Further out -- around 2015, Ernst estimates -- printed circuits could end up in some very interesting places, such as flexible e-book readers that can be rolled up when not in use or clothing made of a solar-cell fabric that can charge a music player or cell phone. Market analysis firm IDTechEx forecasts that sales of these flexible printed circuits will grow from $1 billion in 2010 to $45 billion in 2016 and show up in a variety of devices.

IBM's Guha also sees a bright future for printed circuits. "Anytime you remove a clean room from making electronics, it becomes much cheaper," he says. "Cheap and dirty is good enough for many uses, provided that the circuits can be made with acceptable quality."