The GaAs metal-semiconductor-metal photodetector (MSM-PD) with recessed metal electrodes have been fabricated and characterized. The recessed structure allows very short photocarrier sweep-out time because of both a strengthened electric field in the active region and a shortened distance for the photocarriers to reach the electrodes. Improved high-speed performance and enhanced peak amplitude in the temporal response can thus be obtained simultaneously. There is about a 60% and 50% improvement in the fall time and peak amplitude of the temporal response at 5 V bias over the conventional device, respectively. The measured results also show that high-speed operation can be achieved at a lower bias voltage for the GaAs MSM-PD with recessed metal electrodes as compared to the conventional one. Two-dimensional simulation was carried out to give an insight into the operation principle of this device. (C) 1996 American Institute of Physics.
