Gallium-arsenide diffused diodes

Small-area mesa-type gallium-arsenide diffused diodes for use as variable reactances are described. These devices have been made by the diffusion of zinc into n-type material with net impurity density ranging from atoms/cm³through atoms/cm³. Cutoff frequencies, fco, above 100 kilomegacycles have been obtained for diodes made from this material. The fabrication of these devices will be described in detail with especial reference to diffusion techniques, methods of making ohmic contacts, and etching techniques. Packaging procedures used and their relation to problems arising in both the fabrication of these devices and the measurements made upon them will be discussed. The electrical characteristics of these diodes will be discussed as well as the microwave measurement techniques used in evaluating the cutoff frequencies.