Importance and Requirement of Frequency Band Specific RF Probes EM Models in Sub-THz and THz Measurements up to 500 GHz

IEEE Trans. Electron Devices

Yadav

Deng

et al. 2020

Self Cite

In this paper, we present on-wafer TRL-calibrated measurements of silicon test structures fabricated using STMicroelectronics' B55 technology up to 500 GHz. The structures are fabricated in two subsequent runs and the respective structure in each run has a different design. The improvements in the test structures layout design are presented on the terminal capacitances of "open-M1", which is an important test structure for the de-embedding of the transistor accesses. The improvements are examined using HFSS electromagnetic (EM) simulations, including the RF probe models and the neighboring structures.

Section: Resultsmentioning

confidence: 99%

“…After creation of the 3D models of each structure, simulation is carried out much like described in [24]. Thanks to the optical microscope imaging, several G-S-G probe models replicating the GGB® Picoprobe RF probes with a 50/100 µm pitch for each band up to 500 GHz have been designed in HFSS [25].…”

Section: Em Simulation Proceduresmentioning

confidence: 99%

Silicon Test Structures Design for Sub-THz and THz Measurements

IEEE Trans. Electron Devices

Yadav

Deng

et al. 2020

Self Cite

“…In contrast, the calibration in WR3.4 and 2.2 band gives more realistic results. As shown in [19], this is attributed to highly downscaled probes restraining and guiding the EM field towards the structure in a confined way. In a second step, the EM-SPICE co-simulation is carried out.…”

Section: A Analysismentioning

confidence: 95%

“…3. It is an optimized version of the test structures compared to [19]: it is dedicated to on-wafer TRL calibration with a large space between structures and it uses staggered test structures to reduce the influence of adjacent structures. Also, the pad geometry has been optimized to be compatible with 100 and 50 µm pitch for millimeter-wave and sub-millimeter-wave measurements.…”

Section: A Test Structuresmentioning

confidence: 99%

Analysis of High-Frequency Measurement of Transistors Along With Electromagnetic and SPICE Cosimulation

Fregonèse

IEEE Trans. Electron Devices

Yadav

et al. 2020

Self Cite

THz silicon based electronics is undergoing rapid developments. In order to keep this momentum high, an accurate and optimized on-wafer characterization procedure needs to be developed. While evaluating passive elements, the measured sparameter data can be verified by a direct use of EM simulation tools. However, this verification requires to precisely introduce part of the measurement environment such as the probes, the pads and access lines to accurately predict the impact of calibration and layout for on-wafer measurements. Unfortunately, this procedure is limited to passive elements. Hence, in this work, we propose a new procedure to emulate the measurement of active devices using an electromagnetic-SPICE co-simulation. By this method, one can clearly highlight that a measurement artefact that was observed for the transistor measurement can be reproduced. One of the most representative example of measurement artefact involves the measurement and estimation of fMAX which is not constant over all frequency band. Also the measurement is difficult to perform above 40 GHz. This typical problem is now undoubtedly attributed to the probe-to-substrate coupling and probe-to-probe coupling which are strongly dependent on the probe geometry. Finally, this co-simulation procedure evidently underlines the need for an optimized de-embedding procedure above 200 GHz.

“…In the same way, this effect can be completely suppressed by changing the probe geometry used below 220 GHz by using the front-end geometry of the WR3.4 or WR2.2 probe. Therefore, the two calibration kits developed in [10], [18] and the one from this paper are obviously incompatible with the 220 GHz Picoprobe from GGB probe, and the calibration kits deserve to be redesigned taking into account the geometry of this probe. Another solution would be to use better designed probes.…”

Section: Models Of Probes In the Whole Frequency Bandmentioning

confidence: 99%

THz Characterization and Modeling of SiGe HBTs: Review (Invited)

Fregonèse

Deng

IEEE J. Electron Devices Soc.

et al. 2020

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This paper presents a state-of-art review of on-wafer S-parameter characterization of THz silicon transistors for compact modelling purpose. After, a brief review of calibration/de-embedding techniques, the paper focuses on the onwafer calibration techniques and especially on the design and dimensions of lines built on advanced silicon technologies. Other information such as the pad geometry, the ground plane and the floorplan of the devices under test are also compared. The influence of RF probe geometry on the coupling with the substrate and adjacent structures is also considered to evaluate the accuracy of the measurement, especially using EM simulation methodology. Finally, the importance of measuring above 110 GHz is demonstrated for SiGe HBT parameter extraction. The validation of the compact model is confirmed thanks to an EM-spice cosimulation that integrates the whole calibration cum deembedding procedure.