In this paper a novel photodetector at 1550 nm, working at room temperature and completely silicon compatible, is reported. The detector is a resonant cavity-enhanced structure incorporating a Schottky diode back-illuminated and its working principle is based on the internal photoemission effect. The device performances in terms of responsivity are numerically calculated for different values of bottom reflectivity. Finally, a preliminary device was realized and characterized in order to validate the theoretical results.