An analysis of inertial inductance in a junction diode

When the injected carrier concentration is not small compared to the equilibrium concentration, drift and diffusion processes interact, and an inductance is developed in the base region. This phenomenon has been analysed by calculation of the small-signal impedance of a PIR diode. Simple expressions have been obtained for the case
\omega \ll 1
as well as
\omega \gg 1
, where ω
²
is the product of the radian frequency and the diffusion transit time. For intermediate values of ω, the impedance contains an integral which has been expressed in terms of a tabulated function. Curves are presented showing the diode impedance as a function of frequency and forward bias. For low bias the reactance is capacitive, but with increasing bias, provided the frequency is not too high, the reactance becomes inductive. The resistive component also shows a frequency dependence. The maximum inductive reactance occurs when
\omega \approx 1
and the
Q
does not exceed 1.