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

Abstract

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 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> deg <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> and barrier heights of 1.03, 0.97 and 0.91 volts, corresponding to the 〈111〉, <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\langel \overline{111}\rangle)$</tex> 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.