In this letter, we report the successful growth of an ultrathin organic film onSi(100)-2×1by reactive coupling of polyimide precursors. Using the molecular layer deposition technique, 1,4-phenylene diamine and pyromellitic dianhydride were sequentially dosed on cleanSi(100)-2×1under ultrahigh vacuum conditions. The interfacial imidization was initiated by thermal curing at 200 °C. High resolution electron energy loss spectroscopy was employed to identify surface species. The spectra show clearly, that an oligimide chain has been formed which stands upright on the substrate. The chain bonds to the silicon substrate via a Si–(NH)–C linkage. ©1997 American Institute of Physics.