Motorola Labs Announces Breakthrough in New Transistor Material Will Extend the Silicon Revolution; Will Lead to Smaller, More Powerful Devices That Consume Less Energy.

TEMPE, Ariz.--(BUSINESS WIRE)--Dec. 1, 1999--

Motorola Labs announced today that it has built the world's thinnest functional transistor using a new class of semiconductor materials that will enable future transistors to be exponentially smaller and faster while consuming less power. Motorola Labs has successfully built a working device that uses a class of perovskite materials never before used in a transistor. This represents the first fundamental change in the materials used to build transistors for the past 30 years.

The new technology enables the development of a transistor with an effective thickness that is initially three-to-four times thinner than those built with today's conventional semiconductor materials. While this technology is still at an early stage of development, it has already produced working devices that are electrically much thinner than those made with existing technology. Perovskites (pronounced: Per-AHV-skites) are a class of crystalline oxide materials with unique material properties.

The advance in shrinking the effective thickness of a transistor without rapidly increasing the leakage current will allow computer chips to continue to be significantly reduced in size and power consumption for many years to come. This development could enable future integrated circuits to be faster and more powerful while operating from the voltage of a single battery.

"As devices continue to shrink in size, the gate oxide of the transistor also needs to become thinner. However, we are quickly reaching the limit where we can no longer thin the silicon dioxide which has been used as a gate insulator for the last 30 years," said Jim Prendergast, vice president and general manager of Motorola's Physical Sciences Research Lab (PSRL). "The solution is to use a new family of materials that appear electrically to be much smaller than their actual physical thickness."

This is accomplished by using materials with a higher dielectric constant (high k materials) than the standard silicon dioxide. By growing a strontium titanate crystalline material on silicon substrates, Motorola Labs has demonstrated electrical properties over 10 times better than equivalent silicon dioxide.

Motorola's PSRL is also in partnership with engineers from the DigitalDNA(TM) Laboratories of Motorola's Semiconductor Products Sector to determine the route to manufacturing for the new technology.

The key to this development was computer simulation of each individual atom at the interface using some of the most powerful simulation techniques available today. By understanding the behavior of the atoms in the structure, Motorola Labs was able to solve fundamental problems that have frustrated other attempts at using such new materials for a gate insulator.

This is the first time that such detailed computer simulations have been applied to the design of such an interface. The computer predictions were confirmed with carefully controlled experiments and advanced analytical capabilities in cooperation with the University of Arizona and the Stanford Synchrotron Radiation Laboratory.

Motorola, Inc. (NYSE:MOT) is a global leader in providing integrated communications solutions and embedded electronic solutions. Sales in 1998 were $29.4 (USD) billion. More information on Motorola is available at http://www.motorola.com/

Technical Background

Although perovskite materials have been explored for many years in the industry, Motorola Labs is the first to produce a working CMOS transistor to prove the concept. Initial attempts by Motorola Labs to produce a working transistor were successful. The resulting device, which demonstrated electrical properties superior to existing CMOS transistors, performed close to theoretical predictions.

Perovskites are a class of crystalline materials having a metal atom inside an oxygen octahedron structure. This structure gives them unusual properties such as high dielectric constant and even ferroelectricity depending on the specific atomic elements incorporated. Perovskites, while rare in nature, are found in Tanzania, Brazil, and Canada. In the lab, these structures are made artificially by building them up one atomic layer at a time, resulting in a pure and nearly perfect crystal.

In order to get the crystalline oxide material to match up with the silicon crystal, the interface between the two materials must be precisely controlled. Motorola used molecular beam epitaxy (MBE) to research the physics involved to precisely join the two dissimilar materials into a single crystal structure. The strontium titanate crystal needs to be rotated 45 degrees on the silicon surface and the number of defects at the interface must be less than one atom out of place for every ten thousand atoms.

Motorola Labs also demonstrated that it can grow these materials on silicon wafers up to 8 inches in diameter. This is the first time that MBE has been used successfully on large diameter wafers of this size. The precision of this technique produced layers in which the thickness varied only one layer of atoms across an entire wafer.