High-speed metal-semiconductor-metal photodetectors on InP:Fe

Metal-semiconductor-metal (MSM) photodetectors on semi-insulating InP:Fe with a lateral planar structure have been fabricated. Laterally structured photodiodes are formed with interdigitated contact fingers. The detectors exhibit low dark currents of about 10 nA, an impulse response of 26 ps FWHM (full-width of half-maximum), and an internal quantum efficiency of 80%, all at 10 V bias. An electrical cutoff frequency of 40 GHz for the packaged detectors is obtained from s -parameter measurements, demonstrating that the response time is not limited by the parasitic elements of the devices