PLANAR MILLIMETER-WAVE EPITAXIAL SILICON SCHOTTKY-BARRIER CONVERTER DIODES

Silicon Schottky-barrier junctions useful as down-converter diodes in the 5-6 mm-wavelength region have been fabricated by planar techniques. The rectifying junctions were formed by the interface between a low-temperature, solid-solid, palladium-silicon reaction product and a very thin (∼ 0.5 μm) low-resistivity epitaxial silicon layer. The junctions were 4 μm in dia. and were about 0.25 μm below the surface of the epitaxial layer. Zero-bias cutoff frequencies were in the range of 500-800 GHz. When mounted in suitable millimeter-waveguide down-converter circuits, the minimum measured conversion loss (51.7-1.3 GHz) was about 6.5 dB, and the minimum value of the product (conversion loss) times (noise temperature ratio) was about 7.5 dB. These values are at least 1 dB worse than values of the same quantities obtained by the use of millimeter-wave planar gallium arsenide Schottky-barrier diodes in the same circuits. © 1968.