Barrier Capacitance and Built-in Voltage of Tunnel Diodes

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Abstract
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, \frac{1}{C^{2}}=\frac{2(N_{A}+N_{D})}{q\varepsilon\varepsilon_{0}N_{A}N_{D}}[V B +V a -\frac{kT}{q}{\frac{F_{3/2}(\zeta_{p})}{F_{1/2}(\zeta_{p})}+\frac{F_{3/2}(\zeta_{n})}{F_{1/2}(\zeta_{n})}}], 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.