The transistor, a key component in microchips, uses a modified design and IBM's proven silicon germanium (SiGe) bipolar technology to achieve speeds of 350 GigaHertz (GHz). IBM's new transistor performs nearly 300 percent faster than today's production devices, and is 65 percent faster than previously reported silicon transistors. A fingernail-sized microchip can hold millions of transistors.
IBM anticipates the new transistor will lead to communications chips with speeds of more than 150 GHz in about two years. The transistor is also expected to result in substantially lower power consumption and lower cost for communications systems and other electronic products.
"The industry recognizes the importance of SiGe technology, and everyone is racing to add it to their arsenal," said Bernard Meyerson, IBM Fellow and Chief Technologist, IBM Technology Group. "SiGe is imperative for true system-on-chip designs that pull together standard logic circuitry and higher-speed wireless communications circuitry. And while others are introducing their first versions, this is IBM's fifth generation of SiGe technology."
IBM will present details of the technology in a paper, titled "SiGe HBTs with Cut-off Frequency Near 300 GHz" at the International Electron Devices Meeting (IEDM) held in San Francisco, Dec. 9-11, 2002.
Transistor speeds are determined primarily by how quickly electrons pass through them. This is dependent on the semiconductor material used to fabricate the transistor and the distance electrons must travel through it. The material used in most standard transistors is silicon. In 1989, following pioneering research work conducted at IBM's Research Division, IBM introduced an improvement to the silicon by adding germanium to speed electrical flow, improving performance and reducing power consumption. With this new achievement, IBM is combining the use of the SiGe material with an improved transistor design that can shorten the electrical path to help speed up the device.
In standard complementary metal oxide semiconductor (CMOS) transistors, electrons travel horizontally, so shortening the path requires that the transistor be made narrower. This is an increasingly difficult and expensive task that requires new manufacturing tools. In this case, IBM has employed a bipolar transistor -- a different transistor configuration that is critical for chips to drive high-speed wireless communications products. In bipolar transistors, electrons travel vertically, so the speed can be improved by reducing the height -- rather than the width -- of the transistor. IBM used a novel vertical profile scaling technique to reduce the height of the transistor, shortening the path of electrical flow and helping improve performance.
IBM's SiGe chips are built on existing manufacturing lines, allowing the technology to be introduced rapidly and at minimal cost. This has expanded the use of SiGe technology for extending function and battery life in cellular phones and other RF (radio frequency, or wireless) communications products. IBM manufactures SiGe chips at its Burlington, Vt., facility.
In data published by research firm IC Insights in its "2002 McClean Report," the firm estimates that SiGe sales totaled $320 million in 2001 and are projected to grow to about $2.7 billion by 2006. The report estimates that IBM SiGe activity accounted for more than 80 percent of total 2001 SiGe business.