Session: WE3C | Nonlinear Device Modeling |
Chair: | Wayne Struble, Triquint Semiconductor |
Co-Chair: | Matthias Rudolph, Ferdinand-Braun-Institut (FBH) |
Abstract: | The nonlinear device modeling session this year includes compact models of PIN diodes, LDMOS transistors, and heterojunction bipolar transistors. Topics range from physical, thermal, to transit-time effects. |
| | WE3C-01 | Modeling Fast Switching Speed PIN Diodes for RF and Microwave Applications |
1055 | R. H. Caverly, A. M. Reif, Villanova University, Villanova, United States |
| A theory is introduced that integrates DC forward current, emitter recombination and I-region width and radius into a single self-consistent model suitable for fast switching speed PIN diodes. Details on the model are provided so that easy implementation by the reader may be performed. The model is verified with experimental data. |
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WE3C-02 | A Nonlinear Electro-Thermal Model for High Power RF LDMOS Transistors |
1536 | D. Bridges, J. Wood, M. Guyonnet, P. H. Aaen, Freescale Semiconductor Inc., Tempe, United States |
| A new nonlinear, charge-conservative, dynamic electro-thermal compact model for LDMOS RF power transistors is described in this paper. The transistor is characterized using pulsed I-V and S-parameter measurements, to ensure isothermal conditions. The intrinsic model current and charge sources are obtained by integration of the real and imaginary components, respectively, of the small-signal Y-parameters: this yields a charge-conservative model by design. A thermal sub-circuit is used to introduce dynamic thermal dependence, and thermal threshold voltage shift is built in. DC and large-signal validation of the model is presented. |
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WE3C-03 | A Scalable Compact Model for III-V Heterojunction Bipolar Transistors |
1421 | S. R. Nedeljkovic, J. R. McMacken, J. M. Gering, D. J. Halchin, RFMD, Greensboro, United States |
| This paper presents a scalable, large signal compact model implemented in Verilog-A and suitable for III-V heterojunction bipolar transistor power amplifiers. It discusses the DC, self-heating, and charge portions of the model and outlines a novel method to scale a parameter set extracted from a single device to the large area arrays typically used in cell phone handset power amplifiers. This method involves a combination of EM simulations of the interconnect manifolds and scaling of the thermal impedances. |
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WE3C-04 | Large-Signal Hybrid Compact/Behavioral HBT Model for III-V Technology Power Amplifiers |
1493 | T. S. Nielsen, S. Nedeljkovic, D. Halchin, RFMD Inc., Greensboro, United States |
| This paper presents a large-signal hetrojunction bipolar transistor model for III-V technologies. A standard HBT compact model is demonstrated accurate in most regions of operation. At low collector supplies and high input drive levels, however, the compact model fails to accurately predict large-signal RF performance. Model inaccuracies are, through large-signal network analyzer measurements, attributed to minority carrier injection due to forward biased base-collector junction; a phenomenon which is not accounted for in the compact model. A hybrid model is proposed. This is a combination of the standard compact model and an artificial neural network based behavioral model. The artificial neural network is trained to empirically model minority carrier injection in the base-collector junction. Significant accuracy improvement is demonstrated and it is verified that greater accuracy comes at the expense of a very small degradation in execution speed. |
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WE3C-05 | Limitations of Current Compact Transit-Time Models for III-V-Based HBTs |
1200 | M. Rudolph, Ferdinand-Braun-Institut (FBH), Berlin, Germany |
| This paper investigates the accuracy limitations of common compact bipolar transistor models towards higher frequencies. The device under test is a InGaP/GaAs HBT, simulated by the FBH HBT model. The results, however, analogously hold for similar bipolar devices and models. The investigation is based on an analytical approach that explains how the model approximations impact simulation accuracy. A model extension is proposed that improves the model at higher frequencies. Measurements are compared with large-signal model simulations that prove the analytical reasoning and highlight the relevance of the effect under realistic operation conditions. |
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