Submicrometer self-aligned dual-gate GaAs FET

Experimental results show that it is possible to fabricate dual-gate GaAs FET's, with L
g1
= 0.6 µm and L
g2
= 1.3 µm, using conventional photoprocessing equipment, masks, and alignment tolerances. The initial source mesa establishes both the source and drain edges during the ohmic contact metal deposition. These two edges establish the lengths and positions of the two gates in the channel, during the two subsequent evaporations. Initial experimental devices gave reasonably good small-signal microwave performance: 8-dB packaged net gain with less than 6-dB simultaneous noise figure, at 6 GHz.