HIGH-SPEED INGAAS METAL-SEMICONDUCTOR-METAL PHOTODETECTORS WITH IMPROVED RESPONSIVITY AND PROCESS YIELD

High-performance In0.9Ga0.1 P-InP-InGaAs metal-semiconductor-metal pho todectors with semi-transparent Au Schottky contacts are fabricated an d studied. The devices, with an active area of 50 x 50 mu m(2) and dif ferent finger spacings of 2, 3 and 4 mu m, all exhibit high responsivi ties over 0.7 AW(-1) and low dark currents below 10 nA. Extremely line ar photoresponse without low frequency internal gain is also observed in these devices. The novel fabrication process used in this work is s imple and has nearly 100% high yield. A device with a small finger spa cing has also been demonstrated to have improved speed performance wit hout sacrificing its responsivity.