IEEE JOURNAL OF SOLID-STATE CIRCUITS, VOL. 36, NO. 9, SEPTEMBER 2001 1371
Introduction to the 2000 Bipolar/BiCMOS Circuits
and Technology Meeting
T
HIS section of the Special Issue consists of papers solicited from 44 presentations at the 2000 Bipolar/BiCMOS Cir-cuits and Technology Meeting (BCTM), which is sponsored by the IEEE Solid-State Circuits and Electron Device Societies. The seven papers presented here were recommended for pub-lication by the session chairs and co-chairs at the conference.Since the first meeting held in 1986, the BCTM has brought together researchers and engineers involved in bipolar circuits and technology, including device physics and modeling. In this respect, the BCTM is a unique forum where both device and circuit researchers meet and exchange their views and ideas. This interaction is encouraged through conference sessions, a one-day short course held prior to the actual conference, an evening panel discussion, an exhibits hall, and other social events, such as the luncheon.
In the first paper of this section, Bertrand et al.give a detailed analysis of the physical mechanisms involved in ESD stressing of a vertical grounded-base n-p-n bipolar transistor. They utilize 2-D device simulation, square pulse measurements, and photo emission experiments to achieve a physics-based avalanche for-mulation that reproduces the low snapback holding voltage of the vertical grounded-base n-p-n transistor structure under TLP stress. This result is implemented as part of a compact model for ESD protection structures. The model provides a good correla-tion with measured data without introducing the convergence difficulties usually related to ESD stress simulations.
The second paper, by Jos, addresses the developments of power amplifier technology for cellular phones. Dominant issues in this field are PAE, ruggedness, linearity, price, and size. These features are all technology dependent, and, there-fore, different technology options for PA implementations are considered. The paper identifies the need for proper class-AB transistor operation to limit the voltage swing and avoid “early” device breakdown. Moreover, it stresses the importance of reducing the device and connection parasitics for improving PAE. In conclusion, a technological outlook is given for the future of integrated PA functionality by considering two different implementation paths: integration on chip and added functionality in modules.
With the increasing demands on linearity in telecommuni-cation applitelecommuni-cations, the need for more accurate device models is growing. The requirements on compact models and the re-lated parameter extraction for reliable predictions of nonlinear distortion are severe. Not only should these models be able to reproduce the measured device data, but they should also give the correct first and higher order derivatives of the current and charge functions with respect to the nodal voltages. The paper by Paasschens et al. focuses on this topic and considers the
com-pact modeling of output conductance and cutoff frequency of a bipolar transistor based on the physical behavior of the col-lector epilayer. By inclusion of velocity saturation and current spreading effects, and the implementation of an alternative for-mulation of the epilayer behavior, the Mextram 504 model gives a smooth transition at the onset of quasi-saturation, resulting in an accurate description of measured data as well as smooth first and higher order derivatives.
The diversity of telecommunication applications and their in-dividual specification requirements suggests that technologies should be optimized for the final product specifications rather than for individual “small-signal” device characteristics. This type of application-driven technology optimization is the sub-ject of the paper by van Noort et al., in which a bipolar tran-sistor with a nonuniform collector doping profile is investigated for base station applications. The tradeoff between ruggedness and linearity is improved by implementing a spiked doping peak in the lightly doped collector so that the depletion region is bounded for nominal device operation. This yields a more con-stant value for the base–collector capacitance and, consequently, a more linear device operation. When more severe voltage and current conditions are considered, the doping spike will be com-pletely depleted. The depletion region can further extend into the lightly doped epilayer, and the device is thus able to handle the applied terminal conditions. For this paper, van Noort re-ceived the BCTM2000 Best Student Paper Award (decided by a poll of the session attendees).
With the new emerging standards for wireless communica-tion, the following paper by Thomann will be of interest to a large audience; it describes a fully integrated Si-bipolar IF-re-ceiver and IF-transmitter with an on-chip synthesizer for use in third-generation W-CDMA mobiles. Both the receiver and transmitter make use of an on-chip IF-synthesizer with on-chip VCO tuning and tank, as well as fifth-order baseband filters, and comply with ARIB W-CDMA and UMTS standards. The devices are mounted in small 32-pin SMD packages.
Currently, dc power reduction is one of the most important drivers in circuit design for wireless applications: Knapp et al. present two dual-modulus low-cost Si-bipolar prescalers. By careful dimensioning of the transistor areas and current densi-ties, one circuit has been optimized for low power consumption (2 mW) operating up to 2 GHz and a second circuit has been optimized for high speed (12 GHz) and consumes 30 mW of dc power. The prescalers have selectable divide ratios of 128/129 and 256/257, respectively, which make them compatible with standard CMOS PLL circuits.
Key performance parameters of SiGe HBT technology are the reduction of transit time and base resistance, facilitating
Publisher Item Identifier S 0018-9200(01)06101-7.
1372 IEEE JOURNAL OF SOLID-STATE CIRCUITS, VOL. 36, NO. 9, SEPTEMBER 2001
bipolar devices that combine a high cutoff frequency with excel-lent noise performance. The paper by Niu et al. presents exper-imental and modeling results of SiGe HBT devices and shows that the germanium profile can be optimized for improved noise performance. In this paper, focus is placed on the phase noise re-sulting from upconversion of low-frequency noise, which deter-mines the residual phase noise of the local oscillator and mixer circuits.
The next BCTM will be held in Minneapolis, MN, on 1–2 October 2001, with a short course on Sunday, 30 September 2001. I hope to see you there.
ACKNOWLEDGMENT
The Guest Editor would like to express his gratitude to the session chairs for identifying the papers that were solicited for publication, the authors for their commitment to providing and revising their manuscripts within the given time constrains, and the reviewers for their time and expertise, as reflected in their valuable comments and remarks to the authors.
LEOC. N. DEVREEDE, Guest Editor
Delft University of Technology 2600 GB Delft, The Netherlands
Leo C. N. de Vreede was born in Delft, The Netherlands, in 1965. He received the B.S. degree
in electrical engineering from the Hague Polytechnic in 1988 and the Ph.D. degree from Delft University of Technology in 1996.
In 1988, he joined the Laboratory of Telecommunication and Remote Sensing Technology of the Department of Electrical Engineering, Delft University of Technology. From 1988 to 1990, he was involved in the characterization and physical modeling of CMC capacitors. From 1990 to 1996, he worked on modeling and design aspects of HF silicon ICs for wide-band communication systems. In 1996, he was appointed as Assistant Professor at the Delft University of Technology working on the nonlinear distortion behavior of bipolar transistors at the device physics and com-pact model as well as the circuit level, at the Delft Institute of Microelectronics and Submicron Technology (DIMES). In the winter season of 1998–1999, he was a guest of the High Speed De-vice Group of the University of San Diego, CA. In 1999, he became an Associate Professor at the Delft University of Technology, responsible for the Microwave Components Group. His current interest is technology optimization and circuit design for improved RF performance and linearity.
