Scanning probes in nanostructure fabrication

Abstract

Articles you may be interested inMechanical properties of polymeric nanostructures fabricated through directed self-assembly of symmetric diblock and triblock copolymers J. Vac. Sci. Technol. B 30, 06F204 (2012); 10.1116/1.4766916 Development, analysis and control of a high-speed laser-free atomic force microscope Rev. Sci. Instrum. 81, 023707 (2010);Scanning probes have enabled modern nanoscience and are still the backbone of today's nanotechnology. Within the technological development of AFM systems, the cantilever evolved from a simple passive deflection element to a complex microelectromechanical system through integration of functional groups, such as piezoresistive detection sensors and bimaterial based actuators. Herein, the authors show actual trends and developments of miniaturization efforts of both types of cantilevers, passive and active. The results go toward the reduction of dimensions. For example, the authors have fabricated passive cantilever with a width of 4 lm, a length of 6 lm and thickness of 50-100 nm, showing one order of magnitude lower noise levels. By using active cantilevers, direct patterning on calixarene is demonstrated employing a direct, development-less phenomena triggered by tip emitted low energy (<50 eV) electrons. The scanning probes are not only applied for lithography, but also for imaging and probing of the surface before and immediately after scanning probe patterning. In summary, piezoresistive probes are comparable to passive probes using optical read-out. They are able to routinely obtain atomic step resolution at a low thermal noise floor. The active cantilever technology offers a compact, integrated system suited for integration into a table-top scanning probe nanolithography tool.

Advanced electric-field scanning probe lithography on molecular resist using active cantilever

“…5, are actuated by a thermal bimorph actuation principle. [30][31][32][33][34] A metallic microheater (colored red in Fig. 5) forms a sandwich structure (Si∕Si 3 N 4 ∕Al) with the cantilever body.…”

“…In addition, the bi-material thermally driven actuator on the cantilever can not only excite the cantilever at its resonance, but also simultaneously deflect the cantilever at lower frequencies off-resonance. 34,35 The deflection readout of the cantilever is realized by 2-DEG piezoresistive sensors integrated into the base of the cantilever beam (colored green in Fig. 5).…”

Tip Motion—Sensor Signal Relation for a Composite SPM/SPL Cantilever

“…The system of ordinary differential equations (19) represents the motion of the microbeam with a composite structure and thermal actuation. The coupling between mechanical and thermal system is mainly defined by J 4 and J 8 , which represent the thermal actuation and thermal damping of the system. The current i (see (15)) is the excitation signal, which also leads to time dependent coefficients and thus an additional parametric excitation for the thermal subsystem.…”

“…Additionally, the distance between tip and sample is set individually per beam by means of an integrated actuator and thus also yields the topographic information as well as the distance to the sample. Typical approaches for the tip motion estimation multiply the sensor signal with a constant factor to gain the displacement of the tip [4]- [6]. A in-depth analysis regarding this estimation as well as a noncontact SPM or SPL operation with a constant distance of such an array has not been achieved to date.…”

“…This microbeam and the corresponding array have been subjected to intensive experimental investigations, regarding integrated circuit technology, SPM scan process as well as SPL [4], [6]- [10]. To gain a deeper insight in experimentally observed phenomena (e.g.…”