Pulsed laser ablation of silicon: the influence of beam parameters on ablated crater morphology

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Buratin, Stefano (2018). Pulsed laser ablation of silicon: the influence of beam parameters on ablated crater morphology. University of Birmingham. Ph.D.

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Abstract

Laser micromachining is one of the principal fields where the laser capability to change the material morphology is
frequently applied and silicon is still the element most used in the semiconductor and photovoltaic industries despite the recent studies on new materials. Although various models reported in the literature describe the laser material interaction, the relation between the ablated crater morphology and the laser beam parameters remains unclear or does not give methods and equations that can be applied on the engineering environment.
The aim of this thesis is to reduce the knowledge gap of the understanding of three laser parameters (pulse duration, energy beam shape, and polarisation) influence on the ablated crater morphology by providing functions and relations that can be applied in the engineering environment. First, a systematic study on laser pulse duration based on two different functions (i.e. thermal-based and non-thermal based) is carried out, then the impact of the thermal effect on crater morphology of two non-standard energy beam distributions (i.e. round flat-top and square-top) is evaluated, and finally the laser polarisation effects in the non-linear laser ablation regime are explored, providing the engineering environment of new functions and relations between laser beam parameters and crater morphology.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):