Development of scanning probe microscope for Auger analysis

A combined system of the Auger electron analysis and the scanning tunneling microscope (STM) has been developed for both topographical observation and elemental analysis of surface. An STM tip works as a field-emission electron source inducing the Auger process. Conventionally used STM tip has a problem for the Auger measurements; Auger electrons from the sample surface are accelerated toward the sample in the strong electric field between the cathode tip and the sample. We constructed a new special tip with a shield electrode around the cathode tip to prevent the bending of the trajectories of Auger electrons. The field-emission election was ejected from the cathode tip, and the special tip played a role of primary electron source for the Auger electron analysis. We detected silicon Auger electrons successfully from a clean Si(111) surface using a cylindrical mirror analyzer that located behind the special tip. This system works for both STM observation and Auger element analysis by exchanging the tip in vacuum.