Design and development of S-parameter standards for high-frequency nanodevices characterization

This thesis arises from work undertaking to establish reliable and traceable methods for S-parameter measurements of planar circuits. The LNE, in partnership with IEMN, is committed to continually meeting the growing needs of the RF and microwave industry, with a particular focus on the miniaturization of electronic devices. While reducing component size is essential for technological advancement, it also impacts electrical performance. These performance characteristics are assessed using measurement instruments such as vector network analyzers (VNAs), which typically operate with a nominal impedance of 50 Ω. These instruments are optimized for this impedance and are especially sensitive to variations around this nominal impedance. Miniaturization can significantly alter the impedance range, sometimes resulting in extreme values. Measuring a nano-device with a VNA therefore introduces challenges related to impedance matching and measurement sensitivity. In response to these challenges, LNE is expanding its research on VNA measurement methodologies.

The work aims to cover a wider frequency range, target specific impedance domains, and operate at the nanoscale. The objective is to design and develop traceable coplanar nanostructures for vector calibration, supporting an extended impedance range including extreme, low, and high values and to establish associated calibration methods that ensure the metrological verification of the measurement system. This thesis is devoted entirely to the design of new coplanar nanocomponents in a Ground–Signal–Ground (GSG) configuration for VNA calibration, specifically for on-wafer S-parameter measurements. The work addresses the key challenges and advances in RF and microwave on-wafer measurements, with special emphasis on the precise characterization of nanodevices up to 110 GHz. It covers the overall scientific context, motivations, and objectives, the state of the art in RF metrology including the fundamentals of transmission lines and S-parameters RF measurement systems, calibration and deembedding methods, and uncertainty assessment according to the GUM. A particular focus is placed on on-wafer measurement techniques, the influence of device miniaturization, and issues related to highimpedance measurements.

The thesis details the steps involved in designing and fabricating dedicated calibration kits, including the choice of technology, materials, and dimensions, electromagnetic simulations, and validation of calibration algorithms. It also presents the experimental setup for characterizing devices from DC to 110 GHz, measurement protocols, data correction procedures, reproducibility studies, and uncertainty analysis using the TRL method based on both measured and modeled standards. Furthermore, the work focuses on developing new approaches for high-impedance measurements. These approaches are experimentally validated using different calibration kits based on the multiline-TRL method. The new approaches include the well-known Short-Open-Load-Thru (SOLT) method, as well as derivative methods that integrate offsets into the standards, including Short-Short-Short-Thru (SSST), Open-Open-Open-Thru (OOOT), and Highimpedance-Highimpedance-Highimpedance-Thru (HHHT).

The thesis concludes by outlining prospects for extending these methods to new applications. Overall, this research makes both theoretical and experimental contributions aimed at improving the accuracy, repeatability, and applicability of RF and microwave on-wafer measurements, particularly for increasingly miniaturized and high-impedance devices.

S-parameter standards, Vector Network Analyzer (VNA), high frequency, calibration methods, uncertainties, traceability, coplanar waveguide (CPW), nanodevice, metrology, impedance.

Full document (EN) : Thèses françaises (2025ULILN043) ou DOI