A unique filamentary-transistor structure

A unique epitaxial filamentary transistor design, using the substrate as the emitter, described. This structure is made by growing a high-resistivity boron-doped epitaxial layer on a low-resistivity arsenic-doped substrate. Contact is made from the surface to the substrate with a phosphorus diffusion. Ring-and-dot base contacts are made directly on the p-type epitaxial layer with the beam-lead contact process. The spreading resistance under the dot is conductivity modulated when the substrate is adequately biased in the forward direction with respect to the most positive potential point on the edge of the space-charge region in the epitaxial layer. With the dot grounded and a negative bias on the ring, this point lies below the dot. Potential distributions during the off state have been calculated on the computer and will be presented.