Importance of complete characterization setup on on-wafer TRL calibration in sub-THz range

IEEE J. Electron Devices Soc.

Cabbia

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.

Section: Models Of Probes In the Whole Frequency Bandmentioning

confidence: 99%

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

IEEE J. Electron Devices Soc.

Cabbia

et al. 2020

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“…In [8]- [15], effects influencing the calibrated S-parameters such as the multimode propagation, the substrate mode, crosstalk, the differences between the calibration and DUT substrate, the CPW ground width, probe geometry, parasitic coupling due to probe and adjacent test structures fabricated are studied mostly up to 110 GHz for structures fabricated on the Al 2 O 3 /AlN/GaAs/borofloat/ceramic substrates. For structures fabricated on the Si substrate, the impact of the adjacent structures, the probe-to backend environment, the RF probe design, RF pad design and advantage of the on-wafer TRL over the SOLT calibration method in S-parameter measurement are discussed in [16]- [20].…”

Section: Introductionmentioning

confidence: 99%

Investigation of Variation in On-Si On-Wafer TRL Calibration in Sub-THz

Yadav

IEEE Trans. Semicond. Manufact.

et al. 2021

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This work presents possible variations in TRL calibrated on-wafer S-parameters measurements with change in the on-wafer reflect design (pad open to pad short or vice-versa) in the TRL calibration method. The variations in each errorterm values due to the change in the on-wafer reflect in the TRL calibration are examined which shows the source match and reflect tracking as possible error-terms bringing the observed variations in the on-wafer TRL calibrated S-parameter. In order to identify sources introducing these variations in the errorterms values and the S-parameters, TRL calibrated on-wafer S-parameters (S11 and S22) of symmetric structures (both reflects i.e. pad open and pad short) are compared. Further, to develop a deep understanding about variations in error-terms values and in the S-parameters, a comprehensive 3D electromagnetic (EM) simulation study is performed. First, EM simulation analyses considering only one structure in simulation setup are performed to examine role of probe-to-probe and probe-to-substrate couplings. Later, EM simulation study is carried out to analyze the impact of the on-wafer neighours, and the spatial position of the on-wafer neighbours. The EM simulation study shows a strong impact of the coupling of the DUT with the on-wafer neighbours, the spatial placement of the on-wafer neighbours, and the design of the reflect whereby the influence of the probe-to-probe coupling is partially masked by the aforementioned effects.

“…of the neighbouring structures, the substrate materials etc. along with the used calibration and de-embedding techniques [9]- [18]. A dedicated work focused on the improvement of the measurement's accuracy in sub-THz and THz ranges is necessary where an accurate and reliable simulation analysis can play a vital role.…”

Section: Introductionmentioning

confidence: 99%

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

Yadav

IEEE Trans. THz Sci. Technol.

et al. 2020

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In this paper, we present on-silicon structures onwafer measurements up to 500 GHz and a comprehensive electromagnetic (EM) simulation analysis to understand nonideal behaviour in the measured data. The EM simulations are performed in such a way that the simulation setup remains very close to the physical measurement environment where a faithful true EM model of the RF probes is an essential requirement. In this process, four different RF probes used during measurements in the frequency bands 1 GHz-110 GHz, 140 GHz-220 GHz, 220 GHz-325 GHz and 325 GHz-500 GHz are designed in the EM simulator. We also highlight the importance of the frequency band specific probe models to develop a deep understanding of the problems encountered in the sub-THz and THz measurements.