Application of radiation enhanced diffusion to microwave transistor fabrication

The use of preferential Radiation Enhanced Diffusion (RED) of impurities from an n⁺silicon substrate doped with antimony to an n^-silicon epitaxial layer by proton irradiation followed by the phosphorus atom implantation into an n^-epitaxial layer, again followed by the proton irradiation, has been successfully applied to microwave transistor fabrication. This increases the power gain by reducing collector capacitance, Cc, while maintaining high fT, which is difficult to realize by conventional means.