Laser-Induced-Plasma-Assisted Ablation and Metallization on C-Plane Single Crystal Sapphire (c-Al₂O₃).

Xizhao Lu,Chentao Zhang,Gaofeng Zheng,Feng Jiang,Qiuling Wen,Tingping Lei,Zhong Chen,Rui Zhou

doi:10.3390/mi8100300

Xizhao Lu, Chentao Zhang + Show 6 more

Open Access

https://doi.org/10.3390/mi8100300

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Journal: Micromachines	Publication Date: Oct 7, 2017
Citations: 20	License type: CC BY 4.0

Affiliation: Huaqiao University, Xiamen University

Abstract

Laser-induced-plasma-assisted ablation (LIPAA) is a promising micro-machining method that can fabricate microstructure on hard and transparent double-polished single crystal sapphire (SCS). While ablating, a nanosecond pulse 1064 nm wavelength laser beam travels through the SCS substrate and bombards the copper target lined up behind the substrate, which excites the ablating plasma. When laser fluence rises and is above the machining threshold of copper but below that of SCS, the kinetic energy of the copper plasma generated from the bombardment is mainly determined by the laser fluence, the repetition rate, and the substrate-to-target distance. With a lower repetition rate, SCS becomes metallized and gains conductivity. When micro-machining SCS with a pulsed laser are controlled by properly controlling laser machining parameters, such as laser fluence, repetition rate, and substrate-to-target distance, LIPAA can ablate certain line widths and depths of the microstructure as well as the resistance of SCS. On the contrary, conductivity resistance of metalized sapphire depends on laser parameters and distance in addition to lower repetition rate.

Highlights

Single crystal sapphire (SCS) is a hard and transparent material widely used in various fields such as optics, LED, and optoelectronics
S r w where s denotes the laser scan speed, r represents the pulse repetition rate, and w represents the radius of the plasma, which is the size of the metal spots on the SCS surface
When the kinetic energy of plasma is lower than the threshold, ablation will not occur, and copper ions will be deposited on the surface of the sapphire

Summary

Introduction

Single crystal sapphire (SCS) is a hard and transparent material widely used in various fields such as optics, LED, and optoelectronics. Laser-induced-plasma-assisted ablation (LIPAA) [1,2,3] is a method that can ablate the microstructure on sapphire, diamond, and other, similar materials. The energy range of a-plane (2110) sapphire substrates is 0.75–6.5 eV at room temperature [4,5], which obviously differs from those of the c-plane (1110) [6,7,8]. Ed water via ultrasonic cleaning, and dried wiWthhnileitrtohgeesnu.rfaces of the copper target are heated by nanosecond laser pulses, it emits bright gsurWebeshntrialletiegthhatneddsuuheirtfsatotcheeascocoofpptphpeeerrtcaofrlpagmepte,erexrtecaairtcgitnieogtnta;hretehphaltaesaimsteatdo. When the laser energy exceeds the demand of the exciting copper ions, the outer layer. Aplalosmwaerkrienpeetitcition rateeinnedrigcya.teAs haiglohwereorvoevrlearplappinpginragterainted,icaasteusbtshtarat tme-atnoy-tacorgpepterdiostnasnacree apfafertcitciapbaltaintigoinnmthiecraoblsattriuoncture profiolresdaespowsietlilo.n. A lower repetition rate indicates a lower overlapping rate, a substrate-to-target distance affect ablation micro structure profiles as well

Results and Discussion

Relation between Laser Fluence and Microstructure Ablation on SCS

Conclusions