On-wafer small-signal and large-signal measurements up to sub-THz frequencies

Abstract

Recent advances in MMIC technology have opened the possibilities for circuit operation in the THz range. There are numerous examples of BiCMOS and III-V compound device technologies with demonstrated performance beyond 600 GHz. Characterization of such MMIC are predominantly performed on-wafer in a planar environment. However, on-wafer characterization facilities do not fully keep pace with MMIC development in terms of frequency and power.The paper discusses issues involved in on-wafer calibration at mm-wave frequencies, which is the basis for accurate measurements and characterization of active and passive device. Subsequently, the paper discusses mm-wave interconnect characterization. Lowloss interconnects are important for mm-wave MMIC, especially in case of heterogeneous integration. Finally, a novel heterogeneous integration approach of bipolar technologies, using both BiCMOS and InP DHBT processes is presented. This approach heavily relies on low-loss interconnects and accurate device modelling. It will be shown that accurate large-signal models can be efficiently extracted from well-calibrated on-wafer multi-bias small-signal measurements, but verification is difficult due to calibration difficulties at mm-wave frequencies.

High Power InP/Ga(In)AsSb DHBTs for Millimeter-Wave PAs: 14.5 dBm Output Power and 10.4 mw/μm2 Power Density at 94 GHz

“…The characterization of DHBT variants under largesignal excitation (generally, via load-pull measurements) is then essential to accurately model transistor behavior in high-frequency PA circuit design. However, the literature provides relatively few reports of load-pull characterization at frequencies of 94 GHz and higher [5], [6], [7], [8]. While circuits are also desired at frequencies much above W-band, 94 GHz load-pull measurements provide an excellent opportunity to validate device models for PA design.…”

InP DHBT Characterization up to 500 GHz and Compact Model Validation Towards THz Circuit Design

“…Nevertheless, to ensure such high RF potential, the accurate RF characterization of these THz transistors is crucial to confirm the high cut-off frequencies as well as to precisely extract and validate the device compact model, thus enabling millimeter and sub-millimeter-wave IC design. On-wafer measurements are particularly difficult beyond 110 GHz, as discussed in [6] and [7], since unwanted parasitic effects become predominant, which are not totally removed by calibration and de-embedding techniques, and may mask the intrinsic behavior of the nanoscale device. Above 110 GHz, two strategies may be adopted and combined in order to perform accurate on-wafer device measurements at submillimeter-wave frequencies: i) optimizing the test structures' design in order to minimize the unwanted parasitics, ii) developping on-wafer calibration standards on the same substrate as the device to characterize.…”

Design of On-Wafer TRL Calibration Kit for InP Technologies Characterization up to 500 GHz

“…However, the accurate characterization of sub-millimeter- wave devices beyond 110 GHz is particularly critical, as discussed in [11] and [12], as the limitations of calibration and de-embedding techniques and the difficulties of on-wafer measurements at high frequency are increased. Among the characterization works reported for InP DHBTs, the Sparameter measurements are usually performed below 110 GHz, using conventional calibration methods such as Short-Open-Load-Thru (SOLT) [7] or Line-Reflect-Reflect-Match (LRRM) [5][6] on commercial calibration substrates on alumina followed by an Open-Short or Short-Open deembedding step.…”