The impact of subcontinuum gas conduction on topography measurement sensitivity using heated atomic force microscope cantilevers

Abstract

Nanometer-scale topographical imaging using heated atomic force microscope ͑AFM͒ cantilevers, referred to here as thermal sensing AFM ͑TSAFM͒, is a promising technology for high resolution topographical imaging of nanostructured surfaces. Heated AFM cantilevers were developed for high-density data storage, where the heated cantilever tip can form and detect 20 nm indents made in a thermoplastic polymer. The scan height of the cantilever heater platform is typically near 500 nm, but could be made much smaller to improve reading sensitivity. Under atmospheric conditions the continuum models used in previous studies to model the gas phase heat transfer are invalid for the smallest operating heights. The present study uses a molecular model of subcontinuum heat transfer coupled with a finite difference simulation to predict the behavior of a TSAFM system. A direct simulation Monte Carlo model and a kinetic theory based macromodel are separately developed and used to model subcontinuum gas conduction. For the working gas ͑argon͒ the simple macromodel is found to be accurate and is used to predict cantilever operation. This systems-level modeling approach for TSAFM operation can aid data interpretation and seeks to improve microcantilever design.

Thermally actuated buckling beam memory: a non-volatile memory configuration for extreme space exploration environments

“…Previous studies show the pressure and dimension variations in packaging will change the heat transfer coefficient h (Masters et al 2005;Lee et al 2007). This has the potential to change the write time of the device.…”

Free-molecular heat transfer of vibrating cantilever and bridges

“…25,30 The heat transfer coefficient for helium at 288 K, with a thermal accommodation coefficient of 1.0, is plotted in Fig. 13.…”

“…24 However, heat transfer studies have only been conducted numerically on static systems. [25][26][27] …”

Nanoscale thermal lithography by local polymer decomposition using a heated atomic force microscope cantilever tip

“…The heating rate used to generate this TGA data was 10°C/min. fer from the cantilever and in the tip have been reported elsewhere 3,28,[32][33][34][35] and are not reviewed here. The cantilevers have a very high temperature coefficient of electrical resistance that can be used to calibrate the cantilever temperature.…”