A novel photodetector using MOS tunneling structures

A metal/oxide/p-Si structure with ultrathin oxide is utilized as a photodetector. At positive gate bias, the dark current of the photodetector is limited by the thermal generation of minority carriers in the inversion layer. The high growth temperature (1000/spl deg/C) of the gate oxide can reduce the dark current to a level as low as 3 nA/cm/sup 2/. As biased in the inversion layer, the tunneling diode works in the deep depletion region with soft pinning of oxide voltage, instead of the pinning of surface potential, very different from the conventional MOS diode with thick oxide.