Graded-barrier graded-channel InP pseudomorphic power HEMT with 40% power added efficiency and 200 mW output power at 60 GHz
Summary form only given. We present state-of-the-art power and PAE results of InGaAs-InAlAs-InP HEMTs with optimized graded channel and graded Schottky barrier layers which demonstrate, for the first time, that InP-based HEMTs have a considerably better power/PAE combination than GaAs-based HEMTs at V-band. The 0.15 /spl mu/m gate length, eight gate finger, 500 /spl mu/m wide InP HEMTs were measured in a fixture under continuous wave (CW) conditions and showed 23 dBm (200 mW) output power and 40% PAE at 60 GHz with an input power of 17 dBm, a drain bias of 3 V, and a drain current of 125 mA. These results represent the best reported V-band power/PAE performance to date, and a comparison of these results with previously reported results for both InP- and GaAs-based HEMTs is shown. Our state-of-the-art results are attributed to the use of an optimized heterostructure incorporating pseudomorphic graded channel and graded Schottky barrier layers, and the use of compact 15 /spl mu/m/spl times/25 /spl mu/m dry etched through-substrate vias (substrate thickness of 50 /spl mu/m). The heterostructure was designed to achieve high gain, current (Imax) and breakdown voltage; all of which are requirements for a device with high power and PAE.
Very high power-added efficiency and low-noise 0.15- mu m gate-length pseudomorphic HEMTs
0.15- mu m-gate-length double-heterojunction pseudomorphic high electron mobility transistors (HEMTs) for which excellent millimeter-wave power and noise performance were achieved simultaneously are reported. The 50- mu m-wide HEMTs yielded record maximum power-added efficiencies of 51, 41, and 23% at 35, 60, and 94 GHz, respectively. Maximum output powers of 139 mW at 60 GHz and 57 mW at 94 GHz were also measured for 150- mu m-gate-width devices. Finally, minimum noise figures as low as 0.55 and 1.8 dB were measured at 18 and 60 GHz respectively. This is the best power and noise performance yet reported for passivated transistors at millimeter-wave frequencies.<<ETX>>
Calculation of and Errors in the Susceptibility
The measurement of the susceptibility requires three measurements, two of which have to be performed with a substance of known susceptibility. The difference of these last two measurements furnishes the proportionality constant of the apparatus, always employing the same volume, while the difference with the unknown substance gives the required susceptibility.