Laser engineered rippling interfaces for developing microtextures, adherent coatings and surface coupling

J. J. Yu, Y. F. Lu

Research output: Contribution to journalConference article

5 Scopus citations

Abstract

It has been reported that surface roughening is an effective approach to developing microtextures for high performance magnetic media, increased adherence of coatings on large thermal expansion coefficient mismatched substrates as well as enhanced surface coupling for photodetectors. An important prerequisite is that the controllable and reproducible pattern ought to be produced while minimum adverse effects result on materials. In this study, a novel interface ripple pattern is generated on the surface of the single crystal silicon coated with a thin silicon dioxide layer using a KrF excimer laser at different laser parameters. Experimental results show that the ripple period cannot be predicted by the Rayleigh's diffraction condition as conventional laser induced periodic surface structures on solids. The ripple pattern is firstly seeded at the interface and the thin film capping layer will yield ripple structures following the interface rippling. The amount of absorbed KrF laser energy by the SiO2/Si interface is identified to have little dependence on film thickness. Within a certain range of laser parameters, ripple pattern grows with laser fluence or number of pulse linearly rather than exponentially. Of particular interest is that ripple period has been found to have a linear dependence on the film thickness at given laser parameters. This controllable ripple pattern provides a sound solution to the cases that require low laser fluence to prevent materials from damage or demand interface roughening which cannot be achieved by conventional techniques. The uniformity of ripple structures can be controlled by properly adjusting the laser parameters between melting and ablation thresholds and the single crystallinity of the Si substrate remains unchanged under laser irradiation at the fluence up to 1.3 J/cm2.

Original languageEnglish (US)
Pages (from-to)252-262
Number of pages11
JournalProceedings of SPIE - The International Society for Optical Engineering
Volume3898
StatePublished - 1999
EventProceedings of the 1999 Photonic Systems and Applications in Defence and Manufacturing - Singapore, Singapore
Duration: Dec 1 1999Dec 3 1999

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

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