Physics of growth of thin films deposited by laser ablation

Waldemar Mróz 

Military University of Technology, Institute of Optoelectronic (MUT), Wołoska, Warszawa 02-507, Poland

Abstract

The pulsed laser deposition (PLD) is the new method for producing multi-component and composite surface layers. The short interaction time (tens of nanoseconds), equivalent to the growth time of deposited layer causes that the PLD method is one of the most perspective methods to produce nano-structure protective coatings. This method is commonly used for deposition of bio-materials, ceramics, and intermetallic layers on metallic alloys, but also can be used to produce thin films on plastics. Thin films can be grown by different type of lasers, from CO2 (λ = 10.6 μm) and Nd:YAG (λ = 1.06 μm) lasers, to the large family of excimer lasers, with shortest commercially available wavelength λ = 157 nm (F2 lasers). According to the laser wavelength used for material ablation and power density on the target, different mechanisms of absorption can dominate. Mechanisms of absorption influence on the ion energy, quantity and sizes of droplets, as well as on the quantity and sizes of large parts of material (debris) deposited on the layers. Influence of different laser parameters and substrate surface quality on the topography and morphology of deposited layers will be illustrated by experimental results obtained for the deposition of Ni3Al and FeAl intermatallics.
Experimental conditions like laser fluence, substrate temperature and gas pressure also influence on the process of thin film deposition. To illustrate the above mentioned dependencies, the boron nitride (BN) layers deposited with the KrF laser
(λ = 248 nm) onto silicon substrates will be used. The BN layers have been deposited on the substrates under different temperatures, from room temperatures to the temperature of 700 oC, and for nitrogen atmosphere with the pressure changed from 5 Pa to the 40 Pa. The laser fluence in our experiments was changed between 5 and 14 J/cm2.

 

Presentation: oral at E-MRS Fall Meeting 2003, Symposium G, by Waldemar Mróz
See On-line Journal of E-MRS Fall Meeting 2003

Submitted: 2003-07-03 13:07
Revised:   2009-06-08 12:55