Contactless measurement of schottky barrier heights using secondary electrons

A contactless technique using electron-beam-induced voltage has been developed to measure the barrier heights of Schottky diodes. The method detects the change in the on-set energy of the secondary electrons using a cylindrical mirror analyzer in a scanning Auger microprobe (SAM). Measurements have been carried out in a Si diode with half-high-barrier (platinum) and half-low-barrier (titanium) height metal coverage in order to establish the correlation between the measured energy change to the difference in the barrier heights. Using an electron beam of about 1-μm diameter, a change in the on-set energy of 50 meV can be detected with a lateral resolution of about 1 μm. The fine-beam Auger capability of the SAM enables us to identify in situ the local chemistry change responsible for the barrier height variation. This provides a technique with high spatial and energy resolution for investigating the correlation between the interface chemistry and electrical properties of mixed diodes.