Semiconductor technologies seem to race forward almost without impediment, especially in computer-related applications such as memory chips, logic, and processors. But those semiconductor processes geared for RF and microwave applications continue to advance steadily, even as the markets for these devices weaken, according to the latest set of presentations offered at the upcoming

2002 International Electron Devices Meeting (IEDM). Scheduled for December 8-11, 2002 at the Hilton San Francisco & Towers (San Francisco, CA), the conference features a host of quality presentations from around the world on emerging semiconductor processes of interest to RF and microwave designers, including silicon-germanium (SiGe), silicon-carbide (SiC), and gallium-nitride (GaN) device technologies.

SiGe first came to public attention approximately a decade ago at the IEDM, with announcements by Analog Devices (Norwood, MA, www.analog.com) and IBM Microelectronics (East Fishkill, NY, www.ibm.com) on high-speed data converters and other circuits fabricated with the process. Since that time, the IBM SiGe foundry has won more than dozens of believers (and customers) for its high-frequency SiGe process, which now boasts devices capable of transition frequencies (f_Ts) well in excess of 100 GHz.

This past May, IBM announced the shipment of its 100 millionth chip made with SiGe, produced at the company's Burlington, VT facility. The chip was delivered to test-equipment manufacturer Tektronix (Beaverton, OR, www.tektronix.com). This past summer, the company finalized the largest private-sector investment in New York State history with the completion of a $2.5 billion wafer-fabrication facility in East Fishkill, NY. Featuring 12-in. (300-mm) wafers using low-k dielectrics, copper (Cu) interconnects, and silicon-on-insulator (SOI)-based transistors, the facility is fully automated (requiring some 20,000 sensors to track wafers), but will also add approximately 1000 technical jobs to New York's Hudson Valley. The LINUX-based facility is managed by approximately 1700 microprocessors running at 1 GHz with about 600 TB of memory. An internally developed software program known as SiView controls the manufacturing operations. According to New York Governor George E. Pataki, "I've been to Silicon Valley. They don't have the trees we have. They have earthquakes and their lights go out. The Hudson Valley is a much better place to innovate and work."

In addition to IBM, companies deeply involved in the development of SiGe materials and semiconductors include Maxim Integrated Products (Sunnyvale, CA; www.maxim-ic.com) and Atmel (San Jose; CA, www.atmel.com). Most recently, Intel Corp. (Santa Clara, CA; www.intel.com) announced plans to develop SiGe-based mixed-signal circuits which, combined with the company's expertise in complementary metal-oxide semiconductor (CMOS), would result in high-frequency devices for wireless local-area networks (WLANs), as well as high-speed circuits for optical components operating in excess of 50 Gb/s. Intel's Chairman, Andy Grove, will address IEDM attendees at a luncheon presentation entitled "Changing Vectors of Moore's Law."

Although SiGe is usually associated with lower-power, lower-voltage applications, several companies have explored the use of the semiconductor material for power amplifiers (PAs) and devices. The WPTB48F2729C SiGe power heterojunction bipolar transistor (HBT) from Northrop Grumman Electronic Systems' Advanced Technology Center (Baltimore, MD; www.northrop-grumman.com/es/atc) is designed for pulsed radar applications from 2.7 to 2.9 GHz. Suitable for air-traffic-control (ATC) systems, the transistor is rated for maximum collector voltage of +55 VDC and peak collector current of 14 A. It is configured for common-base operation and will deliver 180-W Class C output power (with 32-W input power) when tested with 60-µs pulses at a 6-percent duty cycle at 2.8 GHz.

SiGe Semiconductor (Ottawa, Ontario, Canada; www.sige.com) also recently unveiled a SiGe PA integrated circuit (IC), the SE2522L, targeted at WLAN amplification. Capable of operating at 100-percent duty cycle, the amplifier delivers +20-dBm linear output power at 2.4 GHz with adjacent-channel power ratio (ACPR) of less than −20 dBm per 100 kHz. Unlike the high-voltage Northrop Grumman device, the SE2522L is designed for a supply voltage of +3.3 VDC.

Several presentations at the IEDM will highlight research advances in SiGe, including a report by J. Bock and associates from Infineon Technologies (Munich, Germany; www.infineon.com) revealing devices with gate delays of less than 5 ps. Designed for mixed digital and analog use, the SiGe bipolar technology achieves f_T of 155 GHz at a breakdown voltage of +1.9 VDC, and a maximum frequency of oscillation (f_max) of 167 GHz with only 4.7-ps gate delay. The researchers will detail a 99-GHz digital frequency divider and a low-noise amplifier (LNA) with 2.2-dB noise figure at 19 GHz.