Batch fabrication of scanning microscopy probes for thermal and magnetic imaging using standard micromachining

Abstract

We present a process for batch fabrication of a novel scanning microscopy probe for thermal and magnetic imaging using standard micromachining and conventional optical contact lithography. The probe features an AFMtype cantilever with a sharp pyramidal tip composed of four freestanding silicon nitride nanowires coated by conductive material. The nanowires form an electrical cross junction at the apex of the tip, addressable through the electrodes integrated on the cantilever. The cross junction on the tip apex can be utilized to produce heat and detect local temperature changes or to serve as a miniaturized Hall magnetometer enabling, in principle, thermal and magnetic imaging by scanning the probe tip over a surface. We have successfully fabricated a first probe prototype with a nanowire tip composed of 140 nm thick and 11 µm long silicon nitride wires metallized by 6 nm titan and 30 nm gold layers. We have experimentally characterized electrical and thermal properties of the probe demonstrating its proper functioning.978-1-4244-5764-9/10/$26.00 ©2010 IEEE

Probe-based data storage

“…At this distance, non-magnetic tip-sample interactions become important, leading to undesired topographic cross-talk. A straightforward solution would be to use a Hall sensor integrated on a magnetic tip [108][109][110][111][112] . For better signal-to-noise ratios, integration of a magneto-resistive sensor at the end of the probe, similarly as in hard-disk recording, is preferred.…”

Electron beam lithography on non-planar, suspended, 3D AFM cantilever for nanoscale thermal probing

“…The ongoing trend in nanotechnology of fabricating nanostructures on non-planar 3D architectures has shown significant potential in various fields. Well-known examples are magnetic force microscopy [8,9], tip-enhanced Raman spectroscopy [10], near-field optical focusing [11], scanning single-electron transistor microscopy [12] and scanning thermal microscopy (SThM) [13][14][15][16][17][18][19][20][21][22][23][24][25] that demand nanofabrication on 3D atomic force microscopy (AFM) probes. Recently, a considerable amount of literature has been published on EBL for creating nanostructures on irregular surfaces [26][27][28][29][30][31][32][33][34][35][36][37][38].…”

Advanced micromachining schemes for scanning probe tips

“…This means that the oxidation rate in a three dimensional corner is lower than the oxidation rate on an edge, which is again lower than the oxidation rate on a flat surface. This effect is used to to sharpen either the tip [17,26,28,29] or the mold [19,[30][31][32], which results in a higher aspect ratio and a smaller tip radius.…”

“…Using this method, tip structures consisting of molded pyramidal wire frames have been developed [46,47]. These wire frames have been used as SPM sensors for thermal and magnetic measurements [32,48,49]. Using the same method, but a different approach, pyramidal tips have been developed with small nanometer scale apertures at the apex of the tip and at the sides of the tip [50,51].…”