Circuit Design and Device Modeling
GaAs-HBT-MMICs up to 80 GHz
Circuits for frequencies up to 80 GHz are realized using the FBH GaAs-HBT-MMIC process. The focus is on low phase-noise monolithic oscillators (VCOs). Beyond the modeling of the active device, the description of the passive elements is a key issue. Therefore, a library for coplanar elements has been developed, which covers the common discontinuities (T-junction, air bridges, ...). The models are derived by means of electromagnetic simulation and verified by measurements.
HBT modeling for GaAs and SiGe
Accurate large-signal HBT modeling is an indispensable tool for circuit design. In order to account for the specific behaviour of III-V HBTs, a new model was developed based on the GUMMEL-POON description. Two effects are most important to accurately simulate these HBTs. The first one is self-heating, the second one is the current dependence of the transit frequency, caused by high current injection into the collector.
Briefly, the FBH HBT model features:
- partition of intrinsic and extrinsic base-collector diode
- non-ideal base currents
- self-heating and thermal interaction (by a thermal port)
- current-dependence of base-collector capacitance and collector transit time
- base-emitter and base-collector break-down
- enhanced noise model: improved for 1/f range as well as for RF range of frequency
- scaling with transistor size
- unambiguous analytic parameter extraction from measurements
At the FBH, it is in routine use with in-house and commercial GaAs, InP-based, and Si/SiGe HBTs. Beyond this, it is installed already on several sites worldwide. The Verilog-A code including documentation can be downloaded subject to the following copyright information and disclaimer. Furthermore, the model is available upon request as a Design Kit for ADS, and in source code.
© 2005-2008 FBH. Permission to make copies, either paper or electronic, of these files for personal or classroom use is granted without fee provided that the copies are not made or distributed for profit or commercial advantage and that the copies are complete and unmodified. Other distributing, publishing, or posting on servers requires prior written permission by FBH. By downloading these files, you agree that FBH shall not be held to any liability with respect to any claim by you or from any third party arising from or on account of the use of these files, regardless of the form of action, including negligence. In no event will FBH be liable for consequential or incidental damages of any nature whatsoever.
|Prof. Dr.-Ing. Wolfgang Heinrich|