This paper presents the results of an investigation of the steady-state safe operating conditions for large-signal silicon-germanium (SiGe) heterojunction bipolar transistor (HBT) circuits. By calculating capacitive currents within the intrinsic transistor, avalanche inducing currents through the transistor junctions are isolated and then compared with dc instability points established through simulation and measurement. In addition, calibrated technology computer-aided design simulations are used to provide further insight into the differences between RF and dc operation and stress conditions. The ability to swing the terminals of a SiGe HBT beyond the static $I$ – $V$ conditions coincident with catastrophic breakdown is explained. Furthermore, hot-carrier effects are also compared from multiple perspectives, with supporting data taken from fully realized $X$ -band and $C$ -band cascode driver amplifiers. This analysis provides microwave circuit designers with the framework necessary to better understand the full-voltage-swing potential of a given SiGe HBT technology and the resultant hot carrier damage under RF operation.

Large-Signal Reliability Analysis of SiGe HBT Cascode Driver Amplifiers

This paper presents an improved ultrawideband open-short de-embedding methodology. In contrast to the conventional measurement-based open-short de-embedding method, the presented method is a measurement-calculation hybrid method. First, the open and short de-embedding structures are measured, and the corresponding scattering parameters are obtained. Based on this, lumped-parameter models of the open and short de-embedding structures are established. Then, the established models are modified to solve the over de-embedding problem. Finally, the modified de-embedding structure models are implemented in the scattering parameters of device test structures to achieve ultrawideband de-embedding. To verify the proposed de-embedding method, the method is applied to active devices. The results before and after de-embedding are compared under multiple bias conditions. Furthermore, the results after de-embedding based on the conventional open-short method and the proposed method are compared up to 220 GHz. These results show that using the proposed method can achieve accurate ultrawideband de-embedding up to the terahertz frequency band.

An Improved Ultrawideband Open-Short De-Embedding Method Applied up to 220 GHz

In this letter, a cascade-based de-embedding method with thru-halfthru-short structures is presented for millimeter-wave on-wafer device characterization. Distributed effects of interconnect, discontinuity between pad and interconnect, and transistor-access-via-holes are all well considered using only three dummy structures, and forward coupling is also investigated. By providing both extracted junction capacitors and S-parameter results of 0.5- $\mu \text{m}$ InP DHBT transistor using proposed and existing de-embedding methods up to 220 GHz, better high frequency performance and particularly 21° improvement in phase accuracy for ${\text {S}}_{11}$ as well as 12° for ${\text {S}}_{21}$ at 220 GHz are obtained compared with the state-of-the-art cascade-based method.

A Thru-Halfthru-Short De-Embedding Method for Millimeter-Wave On-Wafer HBT Characterization

We report the fabrication of polymer microfiber with high surface smoothness and length uniformity using molten polymethyl methacrylate (PMMA) by direct drawing technique. PMMA microfibers with diameters ranging from 6 to 12 m and lengths up to few centimeters have been drawn by this method. The microfibers' losses are obtained at 0.37, 0.27, and 0.19 dB/mm for the microfibers with diameters of 6, 8, and 12 m, respectively. (c) 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:820-823, 2015

Fabrication of polymer microfiber by direct drawing

This study presents a physical-based RF equivalent circuit model for CMOS transistors. To increase the model accuracy and extend the effective frequency band, the interconnection effects between the input–output pad and the gate–drain of the transistor are described by using a second-order distributed parameter transmission line equivalent circuit network. Both the extrinsic and intrinsic parameters in the model are extracted from the multibias scattering parameters. Based on the proposed model, the S-parameters are calculated and compared with the experimental results. The comparison shows that using second-order distributed parameter transmission line model can improve the phase accuracy of the model remarkably. The proposed model achieves a high accuracy up to 220 GHz.

A 220-GHz Compact Equivalent Circuit Model of CMOS Transistors

In this paper, a practical scalable cascade-based pad–thru–short deembedding methodology with the characteristic of wave propagation considered is presented for RF device characterization for the first time. Through an analysis, it is found that nonshielding thru and leg lines operate in quasi-transverse electromagnetic and quasi-transverse magnetic modes of wave propagation, respectively. To subtract the leg effect in different lengths based on transmission line parameters without shielding, this difference in operating modes between the thru and leg is addressed in this new method. Compared with a conventional scalable method with shielding, the presented method without violating the process design rules can achieve comparable results. Deembedding accuracy can be maintained without using numerous dummies. Therefore, this scalable deembedding method with simpler layout design and fabrication process is more practical for automatic ON-wafer measurements of different sized devices.

A Simple and Accurate Pad-Thru-Short Deembedding Method Based on Systematic Analysis for RF Device Characterization

A 2.4 GHz high output power and high efficiency power amplifier operating at inductive breakdown in CMOS technology

In this paper, a table-based large-signal model for silicon germanium heterojunction bipolar transistors with the introduction of a breakdown network is presented to describe the avalanche breakdown effect of the base-collector junction on direct current and RF characteristics completely. Input oscillation and output inductive behaviors in the breakdown regime are found to be due to impact ionization induced holes and electrons, respectively. The avalanche breakdown effect and early effect modeled by the breakdown network and output resistance, respectively, can be distinguished in the presented model. In addition, a good agreement between the extracted total input and output resistances at RF and dc is obtained. The validity of this presented large-signal table-based model with multibias intrinsic parameters has been verified through the measured output spectrum and waveform.

SiGe HBT Large-Signal Table-Based Model With the Avalanche Breakdown Effect Considered

In this paper, avalanche breakdown operation has been demonstrated to have a positive impact on RF linearity performance for silicon germanium (SiGe) heterojunction bipolar transistors (HBTs) due to a nonlinear cancellation mechanism between a breakdown inductance and a base–collector capacitance according to the presented Volterra analysis results. As nonlinearity of breakdown inductance increases, linearity can be improved due to its contribution to nonlinear cancellation when variation of an avalanche multiplication factor (M-1) enlarges. In addition to collector current dependence on M-1, collector–base voltage dependence on M-1 is further taken into account to investigate linearity of SiGe HBTs. Linearity at breakdown can be characterized and presented here in a region no matter whether a multiplication factor increases or decreases. The presented analysis results can be beneficial to the reliability investigation for SiGe HBT linearity in the breakdown region.

Investigation of Linearity in the High Electric Field Region for SiGe HBTs Based on Volterra Series

A three-port cascade de-embedding procedure utilized to accurately eliminate the source dangling leg effect of a pseudomorphic High Electron Mobility Transistor (pHEMT) test structure without shielding is presented. The measured device under test (DUT) is de-embedded by using the experimental and electromagnetic (EM) simulated data of dummy structures and their difference is below 1%. In addition, the extracted equivalent circuit parameters of the pHEMT exhibit the frequency-independent characteristics, indicating the dangling leg parasitic is removed accurately. These demonstrate that the presented three-port cascade de-embedding method is valid so that the de-embedded results of the pHEMT can reflect the physical electron trapping effect at microwave frequency. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:77–83, 2014

Three‐port cascade de‐embedding methodology with the dangling leg effect considered for pHEMT electron trapping characterization at microwave frequency

Chie-In Lee

Papers

A Simple and Accurate Pad-Thru-Short Deembedding Method Based on Systematic Analysis for RF Device Characterization

A 2.4 GHz high output power and high efficiency power amplifier operating at inductive breakdown in CMOS technology

SiGe HBT Large-Signal Table-Based Model With the Avalanche Breakdown Effect Considered

Investigation of Linearity in the High Electric Field Region for SiGe HBTs Based on Volterra Series

Three‐port cascade de‐embedding methodology with the dangling leg effect considered for pHEMT electron trapping characterization at microwave frequency