Selective Ablation of Xe from Silicon Surfaces: Molecular Dynamics Simulations and Experimental Laser Patterning

Abstract

The mechanism of laser-induced removal of Xe overlayers from a Si substrate has been investigated employing MD simulations and evaluated by buffer layer assisted laser patterning experiments. Two distinct regimes of overlayer removal are identified in the simulations of a uniform heating of the Si substrate by a 5 ns laser pulse: The intensive evaporation from the surface of the Xe overlayer and the detachment of the entire Xe overlayer driven by explosive boiling in the vicinity of the hot substrate. Simulations of selective heating of only a fraction of the silicon substrate suggest that the lateral heat transfer and bonding to the unheated, colder regions of the Xe overlayer is very efficient and suppresses the separation of a fraction of the overlayer from the substrate. Interaction with surrounding cold Xe is responsible for significant increase in the substrate temperature required for achieving the spatially selective ablation of the overlayer. The predictions of the MD simulations are found to be in a qualitative agreement with the results of experimental measurements of the threshold laser power required for the removal of Xe overlayers of different thickness and the shapes of metallic stripes generated by buffer-assisted laser patterning.

Thermal Decomposition of Tricresyl Phosphate on Ferrous Surfaces

“…This quantitative mismatch is attributable to the much faster heating rate in MD compared to experiments. 18,21,43 Faster heating rates allow for less time at critical temperatures and so cause higher desorption temperatures. [44][45][46] Regardless of their differences, the results from two different experimental methods and…”

Knudsen layer formation in laser induced thermal desorption

“…However, it is not straightforward because the pulsed desorption involves complex time evolution of the density and velocity distributions of desorbed atoms. 23 Sibold and Urbassek have shown by means of the Monte Carlo simulation of the Boltzmann equation that the pulsed desorption flow at an intense flux is well characterized by the above values predicted by the Knudsen layer formation theory. Although previous experimental studies recognized the collision effect in laser desorption, [24][25][26][27][28] the formation of the Knudsen layer in laser desorption has been discussed only by theory and simulations.…”

Lubricant evolution and depletion under laser heating: a molecular dynamics study

“…There are two laser heating regimes to represent the heat irradiation process in MD simulation, i.e., fix heating and temperature thermostat. 47,48 The laser heating used in this work is implemented by adding non-translational kinetic energy (fix heating method) to the lubricants in the center region A. The laser heating duration is 650s (130 000 steps) with a power of 4003/s.…”