Abstract: A resistive level-shifting biasing network is used with a capacitor in parallel to couple FET-based amplifier stages from DC to several GHz in a multi-stage amplifier. The output of the first amplifier stage is connected to the input of the second amplifier stage without a blocking capacitor or level-shifting diodes, allowing a portion of the drain current for the first amplifier stage to be supplied from the second amplifier stage. In a particular embodiment, a distributed amplifier achieved over 20 dB gain from DC to about 80 GHz using three traveling wave amplifier chips.

Abstract: Provided is a process for precisely forming a Schottky barrier gate on GaAs. In the process, a layer of polyimide is spun onto a doped GaAs substrate having a passivating layer thereon. A resist layer is then spun onto the polyimide, and either deep ultraviolet lithography in conjunction with a clear field mask, or direct electron beam exposure, is used to define a gate region. After exposure, the resist is developed, leaving the unexposed portion of the resist in place on the polyimide layer. A metal transfer layer is then deposited over the structure, and the remaining resist is dissolved leaving a hole in the metal transfer layer. The polyimide and the passivating layer are etched down to the surface of the substrate through the passivating layer. The substrate is then dry etched, and then wet chemical etched to form a recess for the Schottky gate. The Schottky gate metal is deposited onto the surface of the structure and through the hole onto the substrate.