FORWARD CURRENT-VOLTAGE CHARACTERISTICS OF SCHOTTKY BARRIERS ON N-TYPE SILICON

An analysis of the forward I-V data of the Schottky barriers formed by Au, Ni and Cr on n-type Si, and of two commercially available Schottky barrier diodes (Fairchild's FH-1100 and Hewlett-Packard's HP-2900) is presented. When the fringing high electric fields at the edge of the diodes are eliminated by using guard rings or mesa structures, their I-V behavior is given by I = Is [exp{ qV k(T + T0)} - 1], where To is a constant. When the fringing high electric fields are not eliminated, thermionic-field (T-F) emission is observed, which increases T0 at low temperatures. Activation energy plots of ln( Is T2) versus I T are not linear for guard ring or non-guard ring diodes implying that the barrier height, φms, varies with temperature. Plots of ln( Is T2) versus I (T + T0) are found to be linear for either kind of diode, which give effective barrier heights, σmso, independent of temperature. For non-guard ring diodes, T0 varied with temperature and it was calculated at each temperature; for guard ring diodes, T0 was approximately a constant with respect to temperature. Therefore, the saturation current Is is given by Is = A*T2 exp{- φMSO k(T + T0)}. A model employing temperature dependence of the barrier height, φms, in the simple Schottky theory is given which explains, qualitatively, T0 and φmso. © 1969.