Abstract

Modulation-doped FETs provide a significant performance advantage over conventional GaAs FETs due to the superior transport properties of the two-dimensional electrons which form the conductive channel in these devices. Table 1 compares the material and device characteristics of different FET devices. At TRW quarter-micron-gate AlGaAs/GaAs MODFETs have been fabricated with cut-off frequencies as high as 80 GHz. These devices exhibit noise figures as low as 2.4 dB at 60 GHz with over 7 dB of associated gain. Power-added efficiencies as high as 42 percent have been achieved at 20 GHz. Figure 1 clearly shows the performance advantage of MODFETs over MESFETs in these RF applications.

© 1987 Optical Society of America