Sb was reported to form an abrupt interface with ultrahigh-vacuum cleaved InP accompanied by anomalously low and high barriers on n- and p-type InP respectively. Since the structural and electronic properties of Bi are similar to those of Sb, the Bi-InP(110) interface may therefore play an important role in the discussion of the Schottky barrier models. Here, the adsorption of Bi at room temperature was studied in situ using X-ray photo-emission (XPS) and Raman spectroscopies up to almost 100 monolayers of Bi coverage. Current-voltage and capacitance-voltage measurements were performed at large coverages of several hundreds of monolayers. While Bi was also found to form an abrupt interface, the overlayer growth mode differs significantly from that of Sb on InP(110). The distinct growth mode is used to explain the higher and lower Schottky barriers for n- and p-type InP respectively. Metal-induced gap states are proposed to be responsible for the final barrier heights.