New approaches to atomic force microscope lithography on silicon

Abstract

We have investigated new approaches to the formation of conducting nanowires on crystalline silicon surfaces using atomic force microscope (AFM) lithography. To increase processing speed and reduce wear of the AFM tip, large-scale structures are formed with a direct laser write setup, while the AFM is used to add the finer nanostructures. Both methods are based on selective oxidation of hydrogen-passivated silicon and subsequent etching to define conducting regions on the surface. This combined technique has previously been implemented on amorphous Si on oxide. To extend the technique to form crystalline silicon nanowires, we have used an arsenic implanted crystalline silicon layer on p-type Si, where the nanostructures are isolated from the substrate electrically due to p-n junction formation. Improvements in the reliability of the AFM lithography technique were achieved by using all-metal tips, which do not wear out as rapidly as metal-coated Si3N4 tips.

Detailed structural study of low temperature mixed-phase Si films by X-TEM and ambient conductive AFM

“…This measurement artefact can be suppressed by the increase to 25 nN (standard measuring value). Contact forces above 50 nN give slightly better homogeneity of local current on rough surfaces, but may have a harmful effect on the life of cantilever metal coating [15], thus complicating the measurement reproducibility.…”

Applications of AFM in Membrane Characterization and Fouling Analysis

“…Additionally, AFM probe tip coatings may wear during measurements, resulting in delamination and artifacts, thereby reducing measurement reliability. To address these issues, all-metal probe tips have emerged as the optimal choice, offering high conductivity and a longer lifespan while maintaining lateral resolution . All-metal probe tips have demonstrated excellent measurement performance and promising applications in various fields, including electronics, thermodynamics, and optics.…”

All-metal AFM probes fabricated from microstructurally tailored Cu–Hf thin films

“…As shown by Birkelund et al [12] the use of all-metal probes for AFM nanolithography resulted in a tenfold increase in lifetime compared to conventional titanium-coated silicon nitride cantilevers. This large enhancement in device lifetime was a result of maintaining conductivity despite continuous wear of the tip.…”

“…Wear of metal-coated AFM tips is also particularly important in SPM-based recording technologies, such as ferroelectric data storage [10,11], which promises ultrahigh areal data density. Increasing the thickness of the deposited metal layer is not a viable solution to increasing probe lifetime, as the tip radius become significantly larger and stresses in the metal layer can induce significant bending of the cantilever, to the extent that alignment in the AFM system becomes impossible [12].…”