Silicon schottky barrier diode with near-ideal I-V characteristics

Metal-semiconductor diodes with near-ideal forward and reverse I-V characteristics have been fabricated using PtSi contacts and diffused guard rings. Typically, for a device with an area of 2.5 × 10⁻⁶ cm² made on an n-type (111) oriented, 0.35 ohm-cm silicon epitaxial substrate, the forward current follows the expression If = Is exp (qV/nkT) over eight orders of magnitude in current with Is = 10⁻¹² A and n = 1.02. The reverse breakdown is sharp and occurs at the theoretical breakdown voltage of p⁺ n silicon junctions of the same n-type doping. The premature breakdown observed in nearly all previous Schottky barrier diodes has been shown to be caused by electrode sharp-edge effects. Besides giving sharp breakdown voltage, the guard ring also eliminates anomalously high leakage currents, yet still retains the fast recovery time characteristic common to other Schottky barriers. Typically, the recovery time measured at 10 ma is less than 0.1 ns, the resolution of the measurement.