Microwave and millimeter wave on-wafer transistor characterization capabilities and HFET CAD model extraction techniques

In the past five to ten years there has been considerable advancement both in measurement capabilities at microwave and millimeter wave frequencies and in measurement data analysis. This has resulted in considerable improvements in the techniques for direct extraction of accurate CAD based models. S-parameter measurements can now be performed on-wafer up to 120 GHz allowing for the extraction of small signal CAD models valid to millimeter wave frequencies. This has resulted in the realization of high performance, 20 dB gain at 110 GHz, MMICs for millimeter wave system applications. Optimized measurements systems for noise parameter measurement at microwave frequencies have been demonstrated. Combined with improved CAD models these also allow for the accurate extrapolation of noise parameters to millimeter wave frequencies. In the area of non-linear characterization, while confined to microwave frequencies, new sophisticated measurement systems are presently being developed. These systems operate in the time domain, thus allowing for measurement not only of RF input and output power but also the RF input and output voltage and current waveforms. This information is leading both to an improved understanding of non-linear transistor dynamic behavior and also to the extraction of accurate non-linear models.