Au-n-Type GaAs Schottky Barrier and Its Varactor Application

Evidence is presented to show that Au-n-type GaAs rectifying contacts are majority carrier rectifiers of the Schottky type. These diodes may be characterized by a Richardson constant of 20–60 amp/cm 2 deg 2 and barrier heights of 1. 03, 0. 97 and 0. 91 volts, corresponding to the 〈111〉, 111) and 〈110〉 orientations of GaAs substrate. GaAs Schottky barrier varactor diodes constructed on epitaxial films may be designed to yield a high cutoff frequency. Performance calculations in a practical case yield a “dynamic quality factor” of 50 at 6 gc under favorable conditions. A “dynamic quality factor” of about 20 at 6 gc should be obtainable with present fabrication technology.