Review Article: Active scanning probes: A versatile toolkit for fast imaging and emerging nanofabrication

Abstract

With the recent advances in the field of nanotechnology, measurement and manipulation requirements at the nanoscale have become more stringent than ever before. In atomic force microscopy, high-speed performance alone is not sufficient without considerations of other aspects of the measurement task, such as the feature aspect ratio, required range, or acceptable probe-sample interaction forces. In this paper, the authors discuss these requirements and the research directions that provide the highest potential in meeting them. The authors elaborate on the efforts toward the downsizing of self-sensed and self-actuated probes as well as on upscaling by active cantilever arrays. The authors present the fabrication process of active probes along with the tip customizations carried out targeting specific application fields. As promising application in scope of nanofabrication, field emission scanning probe lithography is introduced. The authors further discuss their control and design approach. Here, microactuators, e.g., multilayer microcantilevers, and macroactuators, e.g., flexure scanners, are combined in order to simultaneously meet both the range and speed requirements of a new generation of scanning probe microscopes.

Room-temperature single dopant atom quantum dot transistors in silicon, formed by field-emission scanning probe lithography

“…beams. An active (self-sensing and self-actuated) cantilever was used for FE-SPL [40,41], enabling atomic force microscopy (AFM) to be employed for both alignment and inspection [42,43]. The FE-SPL was undertaken using a thermomechanically actuated, piezoresistive cantilever technology [44].…”

Field-emission scanning probe lithography with self-actuating and self-sensing cantilevers for devices with single digit nanometer dimensions

“…3(a)). In this way, resonance and static cantilever deflection can be excited 18,19 . The deflection amplitude of the cantilever vibration as well as the static bending of the cantilever is determined by acquisition of the output signal of integrated piezoresistive deflection sensors 18 .…”

Determination of the mixing ratio of a flowing gas mixture with self-actuated microcantilevers

“…They are free-standing beams a few micrometres in size that undergo changes in their mechanical behaviour as a result of the application of forces and mass deposits. They offer a wide spectrum for sensory tasks: scanning force sensors offering an atomic resolution (Rangelow et al, 2017), force and pressure sensors, acceleration sensors, mass sensors, temperature sensors, IR radiation sensors, bio-and chemical sensors, and flow sensors (Kumar et al, 2014;Steffanson et al, 2012;Waggoner et al, 2007), but also for socalled tip-based nanofabrication (Rangelow, 2006). Due to the possibility of producing these resonant MEMS sensors in extremely small spatial dimensions, they are able to de-tect forces in the nanonewton (nN) range, masses in the femtogram (fg) range and dimensions in the sub-nanometre (nm) range.…”

“…To describe the influence of the surrounding medium, the prediction of the forces acting on the oscillator is of crucial importance. This influence has been investigated in various studies (Sader, 1998;Hiroshi et al, 1995;Maali et al, 2005;Naeli et al, 2009). The emerging forces are described by the increase in mass caused by the moving fluid and the hydrodynamic damping.…”