Experimental studies of metal/InP interfaces formed at room temperature and 77K

Metal/InP interfaces were formed at room temperature (RT = 300K) and low temperature (LT = 77K). A high leakage current was observed for the RT processed metal/InP samples due to its low barrier height (0.35-0.55 eV). An extremely low leakage current and high barrier height (up to 0.96 eV) were achieved when Au and Pd Schottky contacts to n-InP were produced at low temperature. Photoluminescence spectroscopy, Auger electron spectroscopy (AES), electron spectroscopy for chemical analysis (ESCA), and secondary ion mass spectroscopy (SIMS) were used to study the metal/InP interfaces. Photoluminescence spectra showed that there was less surface state density in LT samples. The RT processed sample showed more O and C in the surface region of an Au/InP structure than the same sample processed at LT in the AES spectra. The phosphide out-diffusion was observed in RT processed samples by ESCA. A possible P:O layer on the metal side of the LT processed sample was found by SIMS. Extensive chemical and structural analysis indicated that LT process caused the metal film to be continuous at 50 Å, much better than in standard RT processing.