Low dark current InAlAs/InGaAs metal-semiconductor-metal photodetectors

Metal-semiconductor-metal photodetectors (MSMPDs) have been shown to be important components for integrated optoelectronic receivers due to their high speed performance, low signal-to-noise ratio, and integrability with field-effect transistor technology. Since the signal-to-noise ratio of photodetectors is inversely proportional to the dark current, it is important to devise techniques to reduce the dark current while maintaining high speed performance. In this paper, we have reduced the dark current and also suppressed breakdown effects in InAlAs-InGaAs MSMPDs by placing the contact pads and the tips of the electrodes on an insulating layer of silicon nitride.