Planar-doped gallium-arsenide structures for bulk potential barrier microwave diodes

Diodes with a planar-doped potential barrier are devices with charge transf er by majority carriers for which the height of the potential barrier and t he shape of the current-voltage characteristics can be controlled by means of a definite combination of layers during the growth of the epitaxial stru ctures. These devices have emerged as potential replacements of Schottky-ba rrier diodes for a number of microwave applications. Some typical problems that arise when structures with a planar-doped potential barrier are grown by molecular-beam epitaxy are studied. A process for obtaining the structur es, based on combining vapor-phase epitaxy with molecular-beam epitaxy, is proposed. Various methods are studied for forming ohmic contacts in structu res with a planar-doped potential barrier. A process which provides low con tact resistances (<6X10(-7) Ohm . cm(2)) and a high percentage yield of ser viceable diodes (>95%) is developed. Microwave diodes fabricated with a pla nar-doped potential barrier are compared with Schottky diodes based on gall ium arsenide. (C) 1999 American Institute of Physics. [S1063-7826(99)02003- 7].