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

Diodes with a planar-doped potential barrier are devices with charge transfer by majority carriers for which the height of the potential barrier and the shape of the current-voltage characteristics can be controlled by means of a definite combination of layers during the growth of the epitaxial structures. These devices have emerged as potential replacements of Schottky-barrier 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 structures, based on combining vapor-phase epitaxy with molecular-beam epitaxy, is proposed. Various methods are studied for forming ohmic contacts in structures with a planar-doped potential barrier. A process which provides low contact resistances (<6X10(-7) Ohm . cm(2)) and a high percentage yield of serviceable diodes (>95%) is developed. Microwave diodes fabricated with a planar-doped potential barrier are compared with Schottky diodes based on gallium arsenide. (C) 1999 American Institute of Physics. [S1063-7826(99)02003-7].