Lucent Announces High-Performance Quarter-Micron Silicon-Germanium Technology for Network Transport, Wireless Communications

Lucent Announces High-Performance Quarter-Micron Silicon-Germanium Technology for Network Transport, Wireless Communications

ALLENTOWN, PA. Lucent Technologies (NYSE: LU) Microelectronics Group, the world leader in communications semiconductors, today announced a high-performance silicon- germanium (SiGe) integrated circuit technology for network transport and wireless communications applications. It is manufactured in the company s highly flexible quarter-micron modular complementary metal oxide semiconductor (CMOS) fabrication process for communications systems-on-a-chip (SoC).

The new technology, developed at Bell Labs, features bipolar NPN transistors with cutoff frequencies (or F-sub-t ratings - a measure of transistor switching speed) higher than 70 gigahertz (GHz). For smaller transistors at currents as low as 450 microamps, the cutoff frequencies are still above 60 GHz. Chips recently fabricated in the process demonstrate essential optical network interface functions in support of the synchronous optical network (SONET) OC192 and synchronous digital hierarchy (SDH) STM64 standards of 10 billion bits (gigabits) per second (Gbps) - the rate of today s leading-edge optical networking systems. In addition, Bell Labs has successfully tested circuits at 20 Gbps.

Lucent s SiGe devices can be combined on the same chip with DSP, RF, and memory blocks and other CMOS-based intellectual property cores for SoC implementations. They draw on the same CAD system, ASIC cell and macrocell libraries used in the company s COM-1 quarter-micron CMOS technology, while providing bipolar NPN performance suitable for wired and wireless communications systems for 10 GHz and above.

"This achievement is a significant milestone for the semiconductor industry," said Mark Pinto, chief technical officer of Lucent s Microelectronics Group. "We ve taken pioneering research in silicon-germanium technology from Bell Labs and deployed it as a process module in the same cost-effective CMOS-based technology we use to fabricate our systems-on-a-chip for communications applications."

While other semiconductor companies offer SiGe integrated circuits, Pinto noted that their ICs are typically made in specialized bipolar processes separate from mainstream high-volume CMOS processes, and often at 0.35- and 0.5-micron feature sizes. In comparison, the new Lucent SiGe technology is ahead by one or even two lithography generations.

Lucent is initially targeting the technology at 10 Gpbs SONET/SDH applications, where most high-speed ICs are fabricated in a more expensive gallium arsenide (GaAs) technology. Silicon-germanium technology has the potential to greatly reduce the cost while reducing power dissipation by 50% or more for optical interface ICs in both OC48/STM16 and OC192/STM64 systems. It can also accommodate higher levels of functional integration, allowing smaller form factors and therefore reduced board space.

"This process will enable us to build world-class optical interface ICs at OC192/STM64 and above while paving the way for system-on-a-chip integration with our SONET/SDH digital devices," said Greg Waters, vice president of Networks and Communications in Lucent s Microelectronics Group. "As a result, we ll give our customers the performance levels they need to meet system requirements and provide them with more ways to optimize their systems for cost, power, and board real estate."

Research and development teams collaborated closely for this Bell Labs accomplishment. They started with the regular 0.25-micron silicon BiCMOS technology and added critical features such as super-self aligned (SSA) structures for lower base resistance, SiGe selective epitaxial growth for higher intrinsic transistor switching speed, and self aligned collector implants for minimum collector parasitics. The new technology will be presented by Cliff King at the International Electron Device Meeting (IEDM) in Washington, D.C., next month.

The SiGe technology also includes a modular integrated high-Q inductor featuring Q factors of greater than 15, developed by Bell Labs and described at IEDM by Michel Frei. The ability to optimize and fabricate this component is critical for integrated OC192/STM64 applications. Modularity is maintained by growing a heavily doped latchup-supression buried layer on 10 Ohm-cm substrates to provide high inductor Q levels while preserving the density and latch-up immunity needed for standard CMOS libraries. Both the SiGe NPN transistor and a high-Q inductor are needed to form a complete 10 gbps transceiver.

The SiGe module requires four additional masks over the core COM-1 CMOS process for either a 2.5 volt or 3.3-volt NPN transistor. Using five additional masks over the core process enables both transistors for mixed voltage applications.

Lucent expects to begin offering SiGe devices to customers in the second quarter of 2000, along with design kits based on Cadence tools. Some of these networking devices will include transimpedance amplifiers, limiting amplifiers, clock synthesizers, mulitplexers, demultiplexers, and clock and data regenerators. Lucent also plans to offer a high performance SiGe module as part of its COM-2 0.16-micron process technology sometime in 2001.

Lucent Technologies designs, builds and delivers a wide range of public and private networks, communications systems and software, data networking systems, business telephone systems and microelectronics components. Bell Laboratories is the research and development arm for the company. For more information on Lucent Technologies, headquartered in Murray Hill, N.J., USA, visit its web site at http://www.lucent.com.

Lucent s Microelectronics Group designs and manufactures integrated circuits and optoelectronic components for the computer and communications industries. More information about the Microelectronics Group is available from its web site at http://www.lucent.com/micro.

CONTACT:
Lucent Technologies
Carl Blesch 908/508-8412
E-mail: cblesch@lucent.com

Tom Topalian 908/508-8673
E-mail: ttopalian@lucent.com