A metamorphic HEMT (MHEMT) MMIC technology including circuit applications is presented. The MHEMT layers are MBE grown on 4-inch GaAs wafers. The technology is based on a 50 nm gate length MHEMT and includes a 50 pm substrate backside process with dry etched through-substrate vias. For the electron confinement an InO8GaO2As/lnO53Ga047As composite channel was used. The devices are passivated with BCB and SiN to achieve a median time-to-failure of 2.7 x 1 06 h in air.Cut-off frequencies f, and fmax of 375 GHz were extrapolated for a 2 x 15 pm gate width device.Low-noise amplifiers with more than 1 5 dB gain in the frequency range from 192 GHz to 235 GHz were realized.
A "50 Q" noise figure measurement system has been integrated into a fully automated s-parameter measurement system allowing for fast determination of transistor noise parameters as well as s-parameters, as a function of both frequency and bias. This functionality from such a simple measurement system is achieved using a new analysis technique, based on the "Noise Temperature Model" [l], that allows, after s-parameter measurements and analysis, for the direct extraction of all four transistor noise parameters from a single noise figure measurement.
INTRODUCTIONThe determination of the transistor noise parameters (e.g.
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