In this paper, the design of a novel photodetector at 1.55 µm, working at room temperature and completely silicon compatible, is reported. The device is a resonant cavity enhanced (RCE) structure incorporating a silicon photodetector based on the internal photoemission effect. In order to quantify the performance of photodetector, quantum efficiency including the image force effect, bandwidth and dark current as a function of bias voltage is numerically calculated. A comparison among three different Schottky barrier silicon photodetectors, having as metal layers gold, silver or copper respectively, is proposed. The highest efficiency (0.2%) but also the highest dark current is obtained with metal having the lowest barrier, while for all devices, values of the order of 100 GHz and 100 MHz were obtained, respectively, for the carrier transit time limited 3 dB bandwidth and bandwidth efficiency.