Keysight Technologies, the University of Glasgow, the UK’s National Physical Laboratory (NPL), and Taiwan-based probing specialist MPI Corporation have jointly demonstrated continuous on-wafer characterization of indium phosphide high-electron-mobility transistors (InP HEMTs) spanning from near-DC to 250GHz in a single sweep. The milestone addresses a critical measurement hurdle in semiconductor research by eliminating multi-band hardware swaps and repeated probe placements when evaluating high-frequency active devices.
As compound semiconductor architectures move deeper into millimeter-wave (mmWave) and sub-terahertz (sub-THz) regimes to power 6G communications, automotive radar, and high-speed test systems, device engineers must extract accurate broadband S-parameters across wide frequency bands. Conventional measurement methodologies require segmented waveguide setups, disparate frequency bands, and repetitive calibration routines. These fragmented workflows increase test complexity, risk probe pad wear, and introduce calibration drift that compromises active device compact modeling.
The collaborative setup integrates test hardware, custom calibration software, physical probe stations, and metrology standards into a synchronized measurement platform. Keysight supplied its PNA-X Vector Network Analyzer, a Single-Sweep 250 GHz Frequency Extender, and a Precision Source/Measure Unit (SMU). The University of Glasgow provided advanced InP HEMT devices alongside on-wafer calibration standards, while MPI Corporation contributed wideband on-wafer probing hardware and calibration software. NPL led high-frequency metrology and calibration methodologies to ensure measurement traceability.
The combined architecture achieves continuous broadband characterization with a single probe touchdown. Integrated source filtering and wideband source power calibration maintain signal purity directly at the probe-tip, mitigating reflections and phase errors that routinely distort sub-THz measurements. Thierry Locquette, Vice President of Sales for EMEA at Keysight, stated that sweeping from near-DC to 250GHz in one pass provides researchers with consistent, reliable data necessary to accelerate advanced silicon and compound semiconductor development. Dr. Xiaobang Shang, Principal Scientist at NPL, noted that accurate on-wafer metrology remains foundational as device physics pushes higher into the sub-THz spectrum. MPI Director of Business Development Matthew White emphasized that unifying the probe, calibration, and test instrumentation into a singular system gives engineers the confidence to extract clean broadband parameters rapidly.
For the semiconductor industry, streamlining sub-THz characterization reduces device development cycles for high-electron-mobility platforms. Indium phosphide remains a key material for low-noise amplifiers and high-speed analog front-ends operating above 100GHz. By delivering continuous on-wafer measurements through 250GHz, this unified test framework establishes reliable empirical data pipelines for RF design environments, accelerating the transition of sub-THz compound semiconductors from laboratory prototyping into commercial production.
