Enhancements in semiconductor processes and device structures reveal that integrated circuits (ICs) and discrete devices will continue to reach improved performance levels.
Advances in device technology make possible modern electronic marvels such as the cellular telephone and the Personal Digital Assistant (PDA). Device designers continue to push the envelopes of integration and performance to meet customers' needs for more functions and lower cost in electronic products, and many of these innovations can be seen for the first time at the semiconductor industry's premier conference for device technology: the International Electron Devices Meeting (IEDM). The 2004 IEEE IEDM, scheduled for December 13-15, 2004 in the Hilton San Francisco and Towers (San Francisco, CA) continues this tradition of unveiling some of the most evolutionary and revolutionary semiconductor developments from around the globe.
While the IEDM addresses a variety of technologies for logic, memory, and other semiconductor functions, the areas of most interest to RF designers include large-signal, high-frequency, and microelectromechanical systems (MEMS) devices. For example, in a session on quantum electronics, Walid Hafez and Milton Feng of the University of Illinois at Urbana-Champaign (Urbana, IL) report on quarter-micron-emitter indium-phosphide (InP) single-heterojunction-bipolar-transistor (SHBT) transistor structure capable of 550-GHz cutoff frequency (ft), 257-GHz maximum frequency of oscillation (fmax), and breakdown voltage exceeding 2 V.
Daekyu Yu and colleagues from the Pohang University of Science and Technology (POSTECH, Gyungbuk, Korea) and Intelligent Epitaxy Technology (Richardson, TX) introduced a straightforward fabrication process for creating quarter-micron InP-InGaAs SHBTs with ft of 215 GHz and fmax of 687 GHz while consuming only 8 mA current at 1.5 V. In the area of double HBTs (DHBTs), T. Hussain and associates from HRL Laboratories (Malibu, CA) provided information on a sub-quarter-micron-emitter device with ft of 370 GHz and fmax of 430 GHz while running at only 6 mA collector current and 1.6 V collector-emitter voltage. In the same quantum-electronics session, P. Kurpas and associates from the Institut fur Hochstfrequenztechnik (Berlin, Germany) and United Microwave Semiconductors (Ulm, Germany and Orsay, France) announced flip-chip-mounted GaInP/GaAs HBTs for high-power applications. Devices were mounted on both aluminum-nitride (AlN) and diamond substrates and evaluated by load-pull measurements on packaged cells at 2 GHz and 26 V, with minimum power levels of 11 to 12 W, gain of 11 to 13 dB, and power-added efficiencies of 63 to 71 percent.
High-power gallium-nitride (GaN) devices were the main focus in a second quantum electronics session, with Dimitris Pavlidis of the University of Michigan (Ann Arbor, MI) offering an overview of recent developments at Cree Microwave, Thales, HRL Labs, and Rockwell Scientific. M. Kanamura and colleagues from Fujitsu Laboratories (Atsugi, Japan) unveiled a 100-W AlGaN/GaN high-electron-mobility-transistor (HEMT) amplifier on a conductive N-SiC substrate for wireless applications. The single-chip amplifier yielded 101 W output power with 15.5-dB linear gain from a 60-V supply while exhibiting PAE of 50 percent at 2.14 GHz.
Jorg Scholvin and associates from the Massachusetts Institute of Technology (Cambridge, MA) and IBM (Hopewell Junction, NY) reviewed the RF power potential of a 90-m CMOS process for wireless power-amplifier applications. Load-pull measurements were performed at 2.2 and 8 GHz, respectively. A single digital cell at 2.2 GHz yielded +12.7-dBm output power with about 66-percent PAE, while eight cells in parallel provided +20.2-dBm output power with about 59-percent PAE. A single cell at 8 GHz provides +13.4-dBm output power with 14.6-dB associated gain.
In a session on displays, sensors, and MEMS, Y. Ona and A. Okubora of Sony Corp. (Kanagawa, Japan) reported on reliable, compact polymer-based packages for MEMS switches. When used with capacitive switches, the new packages exhibited less than 0.6 dB insertion loss through 15 GHz . In the same session, Lingpeng Guan and colleagues from the Hong Kong University of Science and Technology (Clear Water Bay, Hong Kong) and Cornell University (Ithaca, NY) offered a glimpse of their fully integrated CMOS and high-voltage RF MEMS technology. Their process was used to integrate a MEMS switch with driver circuitry and control logic on the same chip, which offered 9.5 dB isolation and 0.14 dB insertion loss at 5 GHz.
Finally, in a session on SiGe HBTs, J.J.T.M. Donkers and colleagues from Philips Research Laboratories (Eindhoven, The Netherlands) showed how the addition of a (low-resistance) metal emitter to a SiGe:C HBT device could increase the open-base breakdown voltage. Their research resulted in a device capable of 230-GHz ft with breakdown voltage of 1.8 V. In that same session, M. Khater and associates from IBM showed how to reduce the gate delays of SiGe HBT devices to less than 3.3 ps. For more information on the 2004 IEDM, visit the website at www.ieee.org/confer ence/iedm.