Scanning tunneling microscopy induced local deposition of Si or SiHx on Si(111)-(7×7)

Abstract

In search for a method to produce small artificial surface structures, the scanning tunneling microscope (STM) is used for direct local deposition of Si or Si–Hx species from a SiH4 precursor gas on the Si(111)-(7×7) surface. For material deposition, the tip is brought into the field emission regime and the emitted electron beam is utilized for direct proximal probe lithography at room temperature. The SiH4 precursor is activated by electron bombardment from the STM tip with energies from 10 to 100 eV and emission currents of 30 pA up to 20 nA. This produces local accumulation of the dissociation products on the surface just below the tip. Direct writing of nanostructures with lateral dimensions down to 40 nm is accomplished. Structures with a height from ∼0.36 up to 5 nm are presented. Deposition and imaging of the cracking products are carried out with the same tip.