Fe thin films were grown on p-InP (100) substrates by ion-beam-assisted deposition with the goal of producing sharp Fe/p-InP interfaces with enhanced rectifying properties. X-ray diffraction measurements showed that an Fe layer grown on an InP substrate was polycrystalline, with a relatively sharp interface as seen by Auger electron spectroscopy. Transmission electron microscopy also confirmed the polycrystalline character of the Fe layer and showed that it consisted of small domains. Current-voltage (I-V) measurements performed on Fe/InP diodes revealed good rectification. The Schottky barrier height and the diode ideality factor obtained from these I-V measurements were 0.64 and 1.2 respectively. These results indicate that Fe films grown on p-InP (100) at-room temperature can be used for the fabrication of stable metal gates in new kinds of InP based metal-semiconductor held-effect transistors.