Negative resistance in p-n junctions under avalanche breakdown conditions, part I

A one-dimensional, small-signal analysis of the space-charge region of a p-n junction in which avalanche occurs uniformly is presented. The impedance is found to have a negative real part. The impedance is Well represented by a parallel connection of the depletion layer capacitance, an inductance, and a negative resistance. The admittance of the latter two is proportional to the bias current. The magnitude of the negative is below ten. The negative resistance is due to an intrinsic instability in the avalanching electron-hole plasma. A discussion of the instability and a traveling-wave tube-like amplification is given.