Pulsed laser deposition of thin-film coatings using an antidroplet shield

Abstract

The formation of thin-film coatings of molybdenum diselenide is studied during the deposition of a laser-induced material flux using a shield that is placed on the path of the expansion of this flux in order to trap the droplet fraction. To increase the efficiency of atomic scattering into the shadow zone (behind the shield), deposition is carried out in an inert gas (argon). As the argon pressure increases to 2 Pa, low-density coatings with a developed surface relief form in the shadow zone. When a negative bias voltage is applied to a substrate, the quality of the coating increases substantially. Numerical experiments based on the combination of two computer models that describe physical processes on the atomic level using Monte Carlo methods are performed to reveal the factors that affect the thickness, chemical composition, and structure of the MoSe _x coatings deposited in the shadow zone. The results of calculating the dynamics of the laser-induced atomic flux in a chamber with a shield are used to simulate the coating growth. The deposition of a scattered atomic flux under conditions of surface bombardment by incident particles is shown to substantially increase the coating density and to smooth away the surface relief.