1/f noise in bipolar transistors

Measurements have been performed on the low-frequency, excess, noise in silicon, bipolar, npn transistors at frequencies between 10 -2 Hz and 25 kHz, at temperatures between 77K and 375K and over a wide range of bias. The DC characteristics have also been studied in detail. The excess noise can be represented completely by a single current noise source between the base and emitter with intensity i n 2 =K' 2 I B '2 Delta f/Af gamma where I' B is the non-ideal base current, gamma is an exponent near unity which varies only slightly with temperature, A is the base-emitter contact area and K' is a constant for each device which is independent of temperature and other bias quantities. Discussion is presented of the connection between the excess noise and the non-ideal, recombination current and of the relationship between these results and the various noise models.