Electrical Noise in Semiconductors

Transistors, diodes, and single crystal filaments of germanium have common noise properties: a spectrum'varying inversely with frequency, and strong dependence on the biasing current. Theoretical attempts to explain this noise are reviewed briefly. Experiments with single crystal filaments indicate that the noise resides in the behavior of the minority carrier. In one type of experiment, the correlation of noise voltages in adjacent portions of a filament is quantitatively related, to the lifetime and transit time of minority carrier. In another, the effect of a magnetic field on the noise is found, in accord with calculated changes in lifetime of the minority carrier.