Conformity of Aluminum Thin Films Deposited onto Micro‐Patterned Silicon Wafers by Pulsed Laser Deposition, Magnetron Sputtering, and CVD

Abstract

Complex materials, exhibiting a cocktail of properties, are currently needed for many applications. In this context, new requirements arise in terms of materials processing, such as the synthesis of sub-micrometer objects, or the coating and functionalization of complex surfaces of powders, porous materials, or micro-patterned devices. Depending on the requirements, the aim may be to duplicate the original design of the surface, or to modify it (filling of holes etc.). Physical vapor deposition (PVD) and CVD are promising techniques for the deposition of thin films on such substrates. In order to compare the ability of various deposition techniques to coat complex surfaces, a micro-patterned silicon wafer has been developed. In the present work, aluminum thin films are deposited on this model substrate by two PVD techniques; pulsed laser deposition (PLD) and magnetron sputtering (MS), and by metal-organic (MO)CVD. Scanning electron microscopy (SEM) is performed in order to determine the microstructure and study the thickness conformity.

Efficient Optimization of the Optoelectronic Performance in Chemically Deposited Thin Films

“…Moreover, this method has been shown to be adaptable for the deposition of a single-layer material and scalable for mass production [53,54]. Another advantage of CVD is the conformity of the deposited films (i.e., the thicknesses and grain sizes near the substrate edges are comparable across the sample) [55]. Hence, such films can be deposited on elaborate shapes, inside underlying features, and in high aspect ratio holes.…”

Metallic coatings obtained by Pulsed Laser Deposition through a dynamic prism system

“…In both cases, the plasma plume generation and the subsequent deposition mechanism is previously explained in referenced papers. As Thomman et al proposed [6], when the pulse duration lasts several tenths of nanoseconds (ns), thermal interaction occurs due to the laser energy absorbed by the conduction electrons that collide with the metal lattice atoms. This fact is provoked for the convenient irradiance that induces the plasma plume generation of vaporized species to promote the growing of a film of metal droplets.…”

“…The process takes place inside a vacuum chamber. Different lasers and materials have been employed by researchers in order to obtain a wide variety of samples with different characteristics [2][3][4][5][6][7]. The targets may be disposed stationary or onto a rotational holder.…”

“…The plasma plume moves towards to the substrate, placed in parallel geometry, inducing formation of a thin film on its surface. The distance between the target and the substrate influences the coating formation and homogeneity [6]. In essence, when the laser beam operates under vacuum conditions the induced plasma plume moves evaporated material from the target towards the substrate being coated.…”

“…A wide variety of geometrical configurations have thus been reported in the literature to achieve the PLD process [1][2][3][4][5][6][7]. The most extended PLD method consists, however, in focusing a laser beam with an angle of incidence around 45 degrees onto a metal target placed inside a vacuum chamber [1].…”