Materials processing with intense pulsed ion beams and masked targets

TL;DR

This paper explores optimizing mask designs for intense pulsed ion beams to induce and stabilize phase transitions in materials like silicon through rapid heating and cooling, supported by simulations and analytical models.

Contribution

It introduces a method to optimize mask geometries for targeted material modifications using pulsed ion beams, supported by simulation and analytical scaling laws.

Findings

Peak temperature predictions align with simulations

Scaling laws guide mask design across parameters

Rapid cooling stabilizes desired material phases

Abstract

Intense, pulsed ion beams locally heat materials and deliver dense electronic excitations that can induce materials modifications and phase transitions. Materials properties can potentially be stabilized by rapid quenching. Pulsed ion beams with (sub-) ns pulse lengths have recently become available for materials processing. Here, we optimize mask geometries for local modification of materials by intense ion pulses. The goal is to rapidly excite targets volumetrically to the point where a phase transition or local lattice reconstruction is induced followed by rapid cooling that stabilizes desired materials properties fast enough before the target is altered or damaged by e. g. hydrodynamic expansion. We performed HYDRA simulations that calculate peak temperatures for a series of excitation conditions and cooling rates of silicon targets with micro-structured masks and compare these to a simple analytical model. The model gives scaling laws that can guide the design of targets over a wide range of pulsed ion beam parameters.