Electrical characterisation of metal thin oxide silicon tunnel diodes prepared by rapid thermal annealing

We present electrical results of metal-thin oxide-silicon tunnel diodes fabricated on rapid thermal anneal (RTA) silicon wafers with native oxide layers. The annealing temperature is crucial in deciding whether a Schottky or a tunnel diode is obtained as a result of RTA. In the reverse bias direction, the degree of inversion at the silicon surface was found to depend on the illumination intensity and this has a direct effect on the magnitude of the tunnel current. Devices with gold and aluminium top contacts resulted in minority and majority carrier tunnel diodes, respectively. The capacitance versus voltage measurements confirmed the results obtained from the current versus voltage and X-ray photoelectron experiments. The interface trap and the fixed charge densities of our devices reduced as the annealing; temperature or annealing time increased.