Cell Phone Materials

(Editor's note: This article wasn't illustrated, images are off the the net)

Monday February 12 2:02 PM ET       

Rare Metal Key to Making Smaller Mobile Phones

By Paul de Bendern

HELSINKI, Finland (Reuters) (Copyright 2001, all rights reserved)

Only a few years ago, the mobile phone was a brick-like, unreliable and expensive device targeted at the few with deep, reinforced pockets.

Today, it's a small, light, everyday, inexpensive product used by more than 700 million people, or about 12 percent of the world's population.

What led to this dramatic change?

One important factor was the use of certain metals, such as copper, nickel, palladium, gold and tantalum, to help reduce the size of a cellular phone.

As the robot grasps the live end of the house wire . . .

Yeeeow!

If you knew your chemistry, you simple lout, you would know that tantalum is a super conductor!

Industry experts say that all the technology now packed into a mobile phone, such as batteries, flash memory chips, microprocessors, and liquid crystal displays (LCDs), could have filled a whole office floor less than 30 years ago.

Take, for example, the silver-gray precious metal tantalum, which is mined largely in Australia and Central Africa.

Tantalum, a powder compacted for use in producing passive capacitors, has been a key factor in reducing the size of the mobile phone in recent years.

The expensive and rare powder is used to build these capacitors that regulate voltage at high temperatures.

Demand for this tiny but sophisticated component from the likes of mobile phone giants Nokia and Motorola has pushed the price of the precious metal around 600 percent higher in less than three years, traders say.

Tantalum highlights the importance that "old'' economy precious metals have in the make-up of "new'" economy products, not just in mobile phones but also in portable computers, game consoles and other electronic devices where size is king.

Around one third of the world's tantalum is mined by the Australian company Sons of Gwalia (external link)

Precious Metal Helps Run Heart Of Cellphone

A mobile phone is one of the most intricate devices that people use on a daily basis, but many don't know that it is really a radio -- an extremely sophisticated radio that sends and receives signals while working under very low power.

If you dissect a phone, you will find it contains a battery, a small microphone, a tiny speaker, a liquid crystal display, a keyboard not unlike a TV remote control, an antenna -- used for receiving and transmitting signals -- and a circuit board.

But it is the printed fiber glass circuit board and the content that sits atop it that allow the phone to function. Gold plating covers the surfaces of circuit boards and connectors.

While the cellular phone is mostly made up of plastics, it is run by several powerful computer chips.

Some of the key parts are the microprocessor, the digital signal processor (DSP), the        read-only-memory (ROM), connectors, the radio frequency (RF) power sector and flash memory chips.

But the tantalum capacitor and other passive capacitors are also crucial. About 35 percent of them are made for mobile phone makers, according to industry experts.

They are used as storage vessels, storing energy, ready for use when there is a big surge of energy to a cellular phone.

These components help supply that extra kick of energy for the phone, which the battery cannot provide on its own.

They are also used as an ingredient of superalloys, principally in aircraft engines and spacecraft.

Rock of the modern age: Tantalum

Demand Outstripping Supply

The unexpected surge in demand from mobile phone and computer makers in recent years has boosted the price of tantalum on the metals market, forcing makers of tantalum capacitors, such as American companies AVX Corp. and Kemet Corp. to pass on some of the cost to their clients.

Last year, more than 400 million phones were sold globally, a 45 percent increase on the previous year. In 2001, mobile phone leaders expect over 500 million units to be sold worldwide.

Because cellular phones are not yet recyclable, manufacturers cannot reuse the rare metals for future phones. But plans are underway to allow for limited recycling.

Tantalum prices have also stayed high because demand is outstripping supply and the only        replacement to tantalum capacitors -- ceramic capacitors -- cannot yet be made small enough to fit the dimensions of tiny cellular phones.

Tiny tantalum coated capacitor

"There's no substitute for tantalum that would meet the requirements of mobile phones,'' said Jim McCombie, managing director of A&M Minerals and Metals Ltd., which trades tantalum.

Last year, annual usage of tantalum stood at around five million pounds, up from three million in 1997 and yearly demand is rising by around 15 percent, tantalum traders say.

The rise in demand is also due to a rise in non-mobile phone electronics, especially from makers of small electronic devices.

Prices for tantalum jumped to around $350 per pound last month, up from $40 in 1997, traders said. In the early 1990s the metal traded at around $20 per pound.

But one trader said the price range was now off its highs as financial markets digested news that the mobile phone market would not grow as fast as expected in coming years.

"We may now be past the big peak in tantalum, but demand is still outstripping supply and will do so for the foreseeable future,'' one tantalum trader said. "At least until scientists have found a viable replacement.''

Even if the consumer appetite for mobile phones cools it will still be a big market and tantalum traders expect to see increased demand from Asian manufacturers of electronic gadgets that are also constrained by size.

"Tantalum may not be the flavor of the month, but it's still in fashion,'' London-based McCombie said.  

1965. Man having fun. A Hughes scientist using an early laser to pierce a hole through a sheet of extremely hard tantalum.

FOR RELEASE WEDNESDAY FEBRUARY 07, 2001  

Innovative silicon-chip design from Lucent's Bell Labs may speed rollout and lower costs of wireless networks

SAN FRANCISCO -- Researchers at Lucent Technologies' (NYSE: LU) Bell Labs have created the first all-silicon chips for the part of wireless networks that receives radio signals from mobile handsets. The development, announced today at the International Solid-State Circuits Conference here, could reduce the size and cost of wireless base stations and also could provide network operators with more installation options.

Today's radio receiver in base stations contains 10 to 20 chips comprised of gallium arsenide, which is a substantially more     costly semiconducting material than silicon, yet is needed to satisfy the high-performance requirements of a wireless network. For instance, the radio receiver must handle many weak signals simultaneously, then amplify and filter them before further     signal processing occurs.

"Only recently have circuit designers made silicon chips for radios that rival the performance of gallium arsenide," said Bell Labs researcher Jenshan Lin. "Our silicon-based radio receiver is the first of its kind."

Lin and his colleagues, Olga Boric-Lubecke and Penny Gould, created a radio receiver comprised of only three silicon chips --roughly the size of a quarter - which is 100 times smaller than the gallium arsenide-based radio. The silicon chips also are 10 to 100 times less expensive to manufacture.

"Because base stations with a silicon-based receiver would be smaller, service providers would have greater flexibility when installing them," said Boric-Lubecke. "For instance, the base stations could be placed in less obtrusive locations, such as behind billboards or on top of utility poles. This might help speed the deployment of the mobile Internet as it continues to grow."

The all-silicon fabrication approach also may lead to the combination of a base-station radio receiver and digital signal processor on a single chip. "This would further reduce the base-station cost and move closer to creating a system-on-a-chip solution for base-station radio receivers," Gould said.

The Bell Labs silicon-based radio receiver could be used for all major mobile wireless standards, as well as future third-generation (3G) standards.

For more information, reporters may contact:

Steve Eisenberg, Lucent Technologies, (908) 582-7474     Email:seisenberg@lucent.com

Tiny Resonators May Help Cellphones Shrink

January 31, 2002

By IAN AUSTEN, The New York Times, all rights reserved, Copyright 2002

A CELLPHONE is more than a few chips and a battery. Those things do lurk under the keypad, but most of a phone's insides are taken up by filters, duplexers and resonators - passive components that sort radio frequencies so that you get your calls and not someone else's.

Made from non-silicon materials - ceramics, in some cases - these components present a major obstacle to further shrinking of cellphones.

Some researchers and manufacturers want to replace these passive components with tiny machines called microelectro mechanical systems, or MEMS.

By making components using a variation on the technology that creates microchips, MEMS proponents say they can reduce common annoyances like dropped calls while creating the potential for phones so tiny that they could look like something else.

"In theory, it's possible that wireless phones could become a ring that you put on your finger," said Clark T.-C. Nguyen, an associate professor in the department of electrical engineering and computer science at the University of Michigan.

One of the main functions of passive components in wireless phones is to filter out all radio frequencies - including broadcast radio and television signals - that are outside the band assigned to its system. Then additional filters isolate the specific part of the phone system's frequency band, or channel assigned to carry a user's conversation. Regular cellphone users know that that does not always happen. Noise or bursts of someone else's conversation are usually signs of a filtering failure.

Currently the frequencies are sorted with surface acoustic wave devices, or SAW's. When it is hit by a specific radio frequency, a SAW will vibrate, as Dr. Nguyen put it, like waves on water do.

"Their performance is not great, but it's better than doing the job with integrated circuits," he said.

By contrast, a MEMS device has a tiny internal element that is tuned to vibrate in response to a very specific frequency. "It's just like a guitar string that vibrates only at a certain tone," Dr. Nguyen said.

To measure the selectivity of filters, designers of wireless phones use a rating they call "quality factor," or Q. The higher a filter's Q, the greater its selectivity in isolating frequencies. Integrated circuit filters have a Q of about 20, Dr. Nguyen said, compared with SAW devices, in which the Q rises to 2,000. And MEMS-based filters are at least five times better than SAW's.

Indirectly, better filtering helps reduce the size of a cellphone because lower-quality filtering results in a signal loss that is corrected by more amplification, which drains power. More power means bigger batteries and extra electronics within the phone.

"If you can increase your selectivity," Dr. Nguyen said, "you can lower your power and save money by making the phone simpler."

But it is the MEMS themselves that provide the biggest savings of space. SAW devices come in various sizes but are generally measured in centimeters. A 1-by-1 centimeter square, for example, could easily hold 62,500 of Dr. Nguyen's MEMS resonators.

Despite its small size, Dr. Nguyen said, the tiny vibrating element within his resonator is robust enough to withstand even the worst cellphone abuse. Miniaturization, however, has created another problem. The elements in devices like Dr. Nguyen's have so little mass that at certain frequencies air molecules can interfere with their vibration and reduce their selectivity. To eliminate the problem, commercial versions of his devices will need a low-cost covering that can maintain a vacuum. Dr. Nguyen is a co- founder of Discera, a company based in Ann Arbor, Mich., that is trying to bring the MEMS resonator to market.

Several other companies are working on MEMS resonators as well, including Agilent Technologies (news/quote), formerly part of Hewlett- Packard. Agilent, which has taken an approach different from Dr. Nguyen's, already has a MEMS device in production at a plant in Newark, Calif.

For a vibrating component, Agilent replaces Dr. Nguyen's tuned element with a floating internal membrane in what it calls a "film bulk acoustic resonator." While Agilent's approach results in device that is larger than Dr. Nguyen's, the company's current filters are still 80 percent to 90 percent smaller than comparable SAW devices.

William Mueller, who acts as a liaison between the research and development and the marketing operations of Agilent, said that makers of wireless communications gadgets like wireless card modems for laptop computers and hand-held organizers had shown the greatest interest in the film resonators. "You don't have much height with a card that slips into a computer," Mr. Mueller said.

The Springboard wireless module developed last year by AirPrime for Handspring hand-held organizers uses an Agilent resonator to clean up outgoing signals. And Samsung has incorporated Agilent's technology into a small phone that can be worn as if it were a wristwatch.

Mr. Mueller said that the greatest steps toward ultra-miniature cellphones would come from combining MEMS devices with a phone's electronics in a single unit. Because the film resonator is made with silicon, using techniques similar to the manufacturing of microchips, it is possible - at least in theory - to contain a cellphone on a single tiny microchip.

He said that many complex manufacturing problems would have to be solved before a phone could be created on a single chip. But he said that even people with no interest in talking into a cellphone that looks like a ring would benefit from the introduction of MEMS devices.

"The ultimate benefit," Mr. Mueller said, "is a smaller, lighter phone that works well and works longer between charges."