Silicon crystallinity control during laser direct microstructuring with bursts of picosecond pulses

Jaka Mur (Author), Luka Pirker (Author), Natan Osterman (Author), Rok Petkovšek (Author)

Abstract

Laser ablation and modification using bursts of picosecond pulses and a tightly focused laser beam are used to manufacture structures in the bulk silicon. We demonstrate precise control of the surface crystallinity as well as the structure depth and topography of the processed areas, achieving homogeneous surface properties. The control is achieved with a combination of a well -defined pulse energy, systematic pulse positioning on the material, and the number of pulses in a burst. A custom designed fiber laser source is used to generate bursts of 1, 5, 10, and 20 pulses at a pulse repetition rate of 40 MHz and burst repetition rate of 83.3 kHz allowing for a fast and stable processing of silicon. We show a controlled transition through different laser -matter interaction regimes, from no observable changes of the silicon at low pulse energies, through amorphization below the ablation threshold energy, to the ablation with either complete, partial or nonexistent amorphization. Single micrometer - sized areas of desired shape and crystallinity were defin ed on the silicon surface with submicron precision, offering a promising tool for applications in thAbstract: Laser ablation and modification using bursts of picosecond pulses and a tightly focused laser beam are used to manufacture structures in the bulk silicon. We demonstrate precise control of the surface crystallinity as well as the structure depth and topography of the processed areas, achieving homogeneous surface properties. The control is achieved with a combination of a well -defined pulse energy, systematic pulse positioning on the material, and the number of pulses in a burst. A custom designed fiber laser source is used to generate bursts of 1, 5, 10, and 20 pulses at a pulse repetition rate of 40 MHz and burst repetition rate of 83.3 kHz allowing for a fast and stable processing of silicon. We show a controlled transition through different laser -matter interaction regimes, from no observable changes of the silicon at low pulse energies, through amorphization below the ablation threshold energy, to the ablation with either complete, partial or nonexistent amorphization. Single micrometer - sized areas of desired shape and crystallinity were defin ed on the silicon surface with submicron precision, offering a promising tool for applications in the field of optics.

Keywords

silicon;crystallinity;light-matter interaction;laser processing;direct laser microstructuring;bursts of pulses;picosecond pulses;

Data

Language:	English
Year of publishing:	2017
Typology:	1.01 - Original Scientific Article
Organization:	UL FS - Faculty of Mechanical Engineering
UDC:	535:621.375.826(045)
COBISS:	15709467
ISSN:	1094-4087
Views:	492
Downloads:	150
Average score:	0 (0 votes)
Metadata:

Other data

Secondary language:	Slovenian
Secondary keywords:	silicij;kristaliničnost;interakcija svetloba-snov;laserska obdelava;direktno lasersko mikrostrukturiranje;paketi pulzov;pikosekundni pulzi;
Type (COBISS):	Article
Pages:	str. 26356-26364
Volume:	ǂVol. ǂ25
Issue:	ǂnr. ǂ21
Chronology:	Oct. 2017
DOI:	10.1364/OE.25.026356
ID:	13116227