We report the fabrication and characterization of lateral metal-semiconductor-metal (MSM) photodiodes on an InP substrate. The photoabsorbing layer is made of InGaAs covered by a thin InP Schottky barrier enhancement layer. Schottky contacts for the detectors were formed by the evaporation of Au and patterned using a lift-off technique. The MSM photodiodes exhibit a dark current lower than 200 nA at 15-V bias, an efficient photoresponse up to 1.6 mum, and a fast deconvoluted full width at half maximum response of about 25 ps at 12-V bias.