In a landmark achievement for the future of telecommunications and high-speed computing, a consortium of global technology leaders and academic institutions has unveiled a transformative methodology for characterizing sub-terahertz (sub-THz) semiconductor devices. Keysight Technologies, Inc. (NYSE: KEYS), in collaboration with the University of Glasgow, the National Physical Laboratory (NPL), and MPI Corporation, has successfully demonstrated the continuous on-wafer characterization of indium phosphide high-electron-mobility transistors (InP HEMTs) from near-DC frequencies up to 250 GHz in a single measurement sweep.
This breakthrough addresses one of the most persistent bottlenecks in next-generation hardware development: the complexity of accurately measuring transistor performance as frequencies migrate into the millimeter-wave and sub-THz spectrums. By streamlining the characterization process, this collaboration is poised to accelerate the deployment of 6G, advanced satellite communications, and ultra-high-speed sensing technologies.
The Core Achievement: A Single-Sweep Revolution
Historically, measuring semiconductor devices across ultra-broad frequency bands has been an arduous, multi-stage endeavor. Because conventional measurement setups often lack the bandwidth to capture data from DC to the sub-THz range simultaneously, engineers have traditionally relied on multiple setups, frequent calibrations, and repetitive probe touchdowns. This fragmentation introduces mechanical error, signal degradation, and calibration inconsistencies, often leading to unreliable data for critical device modeling.
The collaborative team’s solution is elegantly simple in its result but highly sophisticated in its execution. By integrating specialized instrumentation with advanced probe station technology, the team achieved a continuous measurement from near-DC to 250 GHz with a single probe touchdown. This elimination of setup changes not only reduces the probability of measurement error but also significantly slashes the time required for data acquisition.
Chronology: From Concept to Calibration
The project was born out of a shared recognition that the roadmap for sub-THz electronics was being hindered by measurement infrastructure. The development process unfolded through a meticulous, multi-phase timeline:
Phase I: Theoretical Modeling and Infrastructure Design
The initial phase focused on identifying the hardware constraints preventing broadband consistency. The University of Glasgow provided the state-of-the-art InP HEMT devices, which served as the testbed for the experiment. During this period, the team aligned Keysight’s vector network analysis capabilities with the precision probing requirements set by MPI Corporation.
Phase II: Metrological Standardization
NPL took the lead in ensuring the measurement framework was scientifically rigorous. Metrology is the backbone of semiconductor advancement; without standardized, traceable measurement, the data remains unrepeatable. NPL’s team worked to define the calibration standards necessary for the 250 GHz threshold, ensuring that the broadband S-parameter measurements could withstand the scrutiny of academic and industrial peer review.
Phase III: Integration and Implementation
The final phase involved the physical integration of the measurement system. By combining high-frequency frequency extenders, advanced probe stations, and proprietary calibration algorithms, the consortium established the final test bench.
Phase IV: Successful Validation
The validation phase, completed recently, confirmed that the system could maintain signal purity and consistent power levels across the entire frequency range. Built-in source filtering and broadband source power calibration were the final pieces of the puzzle, ensuring that the millimeter-wave signals at the probe tip remained stable throughout the entire 250 GHz sweep.
Supporting Data and Technical Significance
To appreciate the significance of this milestone, one must understand the physics of high-frequency characterization. As signals climb toward the 250 GHz range, the wavelength becomes extremely short, making the transition between the probe tip and the device-under-test (DUT) hyper-sensitive to physical placement and environmental interference.
Key Technical Pillars:
- Broadband S-Parameter Accuracy: S-parameters (scattering parameters) are critical for describing how radio frequency energy propagates through a device. Maintaining accuracy from near-DC to 250 GHz is traditionally difficult because different frequency bands often require different types of couplers and bridges.
- InP HEMT Performance: The indium phosphide high-electron-mobility transistor is the gold standard for sub-THz applications due to its high electron mobility and velocity. Measuring these devices with such precision allows researchers to push the limits of noise figures and gain at frequencies that were previously considered "unreachable" for mass-market modeling.
- Signal Integrity: By utilizing built-in source power calibration, the team ensured that the signal delivered to the transistor was clean and consistent. This prevents "overshoot" or "undershoot" in data, which is essential for accurate computer-aided design (CAD) modeling.
Official Perspectives: Bridging Industry and Science
The collaboration represents a rare synergy between private sector innovation and public sector scientific rigor. Leaders from each organization expressed the importance of this milestone for the broader electronics ecosystem.
Thierry Locquette, VP of Sales, EMEA at Keysight Technologies, emphasized the efficiency gained by the new system:
"Characterizing devices continuously from near DC to 250 GHz in a single sweep can significantly simplify the measurement process for researchers developing next-generation semiconductor technologies. By bringing together expertise in instrumentation, devices, probing, and metrology, this collaboration demonstrates a practical approach to generating the consistent broadband data engineers need to accelerate device development."
Dr. Xiaobang Shang, Principal Scientist at NPL, highlighted the critical role of metrology in technological evolution:
"Accurate on-wafer measurement is essential for developing reliable semiconductor devices, particularly as technologies move further into the millimetre-wave and sub-terahertz frequency ranges. We were pleased to contribute NPL’s high-frequency on-wafer metrology and calibration expertise to this collaboration, helping demonstrate a practical route to consistent broadband device measurements."
Matthew White, Director of Business Development at MPI Corporation, spoke to the integration challenge:
"Extending on-wafer characterization to 250 GHz requires the probing, calibration, and measurement platform operating as one seamlessly integrated system. This collaboration demonstrates a practical approach to achieving consistent broadband measurements from near DC to 250 GHz with a single probe touchdown, helping researchers simplify characterization and accelerate device development with great confidence."
Implications for the Future of Tech
The implications of this breakthrough extend far beyond the laboratory walls of the University of Glasgow. As the global push toward 6G telecommunications gains momentum, the ability to characterize transistors at sub-THz frequencies will become the primary competitive advantage for semiconductor firms.
1. Acceleration of 6G and Beyond
6G networks are expected to utilize spectrums far higher than current 5G deployments. This system allows developers to characterize the hardware that will serve as the backbone of 6G, ensuring that the devices can handle the high data throughputs required by future applications.
2. Standardization of Measurement
By providing a clear, demonstrated methodology for broadband characterization, this consortium is setting an industry standard. This will likely lead to the adoption of similar workflows in commercial research and development (R&D) departments, reducing the "time-to-market" for sub-THz hardware.
3. Lowering the Barrier to Entry for Advanced Research
Previously, the cost and complexity of high-frequency characterization were prohibitive for many smaller research entities. By simplifying the process to a single sweep, the consortium has effectively democratized the ability to conduct high-level research, potentially leading to a surge in innovation in the fields of terahertz sensing and imaging.
4. Enhancing Device Reliability
Reliability is the cornerstone of telecommunications infrastructure. Because the new method provides highly consistent S-parameter data, models built from these measurements will be more predictive, leading to more robust device designs that are less prone to failure in the field.
Conclusion
The collaboration between Keysight Technologies, the University of Glasgow, NPL, and MPI Corporation marks a decisive step forward in the quest to master the sub-terahertz frontier. By transforming the complex, error-prone landscape of broadband measurement into a streamlined, single-sweep operation, these organizations have provided the semiconductor industry with a powerful new tool.
As we stand on the precipice of a new era of connectivity—defined by speeds and data densities previously thought to be the realm of science fiction—it is foundational advancements like this one that will define our technological trajectory. With the ability to measure with newfound speed and precision, the roadmap for the next decade of semiconductor evolution has become significantly clearer, paving the way for the innovations that will define the digital landscape of the 2030s and beyond.
