Barrier Capacitance and Built-in Voltage of Tunnel Diodes

Taking the mobile carriers in the depletion layer into account, the barrier capacitance of a tunnel diode is shown to be expressed by the following equation, {1}{C²}={2(NA+ND)}{qεε₀NAND}[V B +V a -kT/q{{F3/2(ζₚ)}{F1/2(ζₚ)}+{F3/2(ζₙ)}{F1/2(ζₙ)}}], where F ν(ζ) is the Fermi integral. The slope of the 1/C 2 vs. V a (applied voltage) curve is in accord with the classical formula (obtained through the ordinary Schottky approximation), but the voltage intercept V c (by extrapolating to 1/C 2=0) is different from the built-in voltage V B . The temperature dependence of the built-in voltage of a tunnel diode is satisfactorily explained.