On the small-signal equivalent circuit of p-n junctions in the condition of finite carriers multiplication

A new version of the equivalent circuit of the space-charge region of the reverse biased p-n junction is evaluated and the expressions for the circuit parameters are given. The basic idea is to separate the equivalent circuit in to the “conductive” and “displacement” branches and in this way the equivalent circuit parameters have physical meaning. The results are applicable to conditions of the finite multiplication factors and unequal ionization coefficients in a wide range of frequency and in the presence of the generation of carriers (thermal or outside induced) in the space-charge region. The numerical results for two complementary abrupt silicon p-n junctions and for low-frequency are given. The equivalent circuit of the multiplication noise source of the p-n junction is discussed.