Using a four-probe scanning tunneling microscope to characterize phosphorus doped ohmic contacts for atomic scale devices in silicon

We use a four-probe scanning tunneling microscope to electrically characterize a Si(1 0 0)2×1 surface, doped with phosphorus. In order to obtain the 2×1 surface reconstruction, the sample is flashed to a temperature of View the MathML source, which is well above the phosphorus desorption temperature. Nonetheless, we find that we are able to obtain good ohmic contact and perform reproducible measurements of the sheet resistivity at the surface. This suggests that phosphorus doped regions may act as macroscopic ohmic contacts to atomic scale devices for in situ four-terminal measurements using a four-probe, UHV STM system.