Construction and Electrical Properties of a Germanium Alloy-Diffused Transistor

The fabrication of high-frequency transistors by the alloy-diffusion method is described. A group of transistors was subjected to an extensive series of measurements in order to establish an equivalent circuit characterizing the transistor for small ac amplitudes at à fixed dc bias. The resulting "physical" T-equivalent circuit is valid up to at least 25 mc. The different circuit elements are discussed with respect to their physical background. A translation from the T-circuit into the electrically more convenient ¿-circuit is also presented.