G. Reisse et al., INFLUENCE OF LN(2) SUBSTRATE COOLING ON OPTICAL-PROPERTIES OF LASER-PULSE-DEPOSITED OXIDE-FILMS, Applied surface science, 86(1-4), 1995, pp. 114-121
Citations number
4
Categorie Soggetti
Physics, Condensed Matter","Chemistry Physical","Materials Science, Coatings & Films
In this paper we will present the results of investigations of the inf
luence of substrate cooling by liquid nitrogen during film deposition
on the optical properties of oxide films prepared by means of laser pu
lse deposition. A CO2-TEA laser at 10.6 mu m wavelength (pulse duratio
n 200 ns, repetition rate 40 Hz, laser fluence 4 X 10(7) W/cm(2) monom
ode) and an excimer laser at 248 nm wavelength (pulse duration 20 ns,
repetition rate 200 Hz, laser fluence 5 X 10; W/cm(2)) were used for t
he evaporation and, respectively, the ablation of sintered oxide targe
ts. Moreover, the growing films were bombarded by oxygen ions of varyi
ng energy and current density. As will be shown, the variation of refr
active index with ion bombardment changed only imperceptibly due to su
bstrate cooling, i.e. films deposited at relatively low ion energy and
current density possess a high bulk-like refractive index and films d
eposited at relatively high ion energy and current density possess a r
ather low refractive index. We could observe, however, that, in compar
ison with uncooled substrates, cooling of the substrates by liquid nit
rogen results in a marked decrease in absorption together with a marke
d increase of the laser damage thresholds of the films at 1.06 mu m wa
velength. For example, the laser damage threshold of hafnia films incr
eased by a factor of 1.5.