Al-Si-N thin films deposited by laser ablation: Effect of plasma parameters on mechanical and optical properties. (March 2018)

• Record Type: Journal Article
• Authors: Rivera, L.P.; Camps, Enrique; Muhl, Stephen; Basurto, Rafael; Zeinert, A.
• Is Part Of: Materials research bulletin. Volume 99(2018)
• Page Start: 306
• Page End: 313
• Publication Date: 2018-03
• Subjects: A. Al-Si-N -- A. Thin films -- B. Pulsed laser ablation (PLD) -- B. Composite hardness -- C. Optical emission spectroscopy; Materials -- Periodicals; Crystal growth -- Periodicals; Matériaux -- Périodiques; Cristaux -- Croissance -- Périodiques; Crystal growth; Materials; Periodicals; 620.11
• DOI: 10.1016/j.materresbull.2017.10.044
• Languages: English
• ISSNs: 0025-5408

Abstract

Graphical abstract: Highlights: Al-Si-N thin films deposited by PLD showed a chemical composition of the films dependent on the silicon plasma density. The change in the direct band gap of the samples was related to the Si content and the maximum was 5.54 eV for 20 at.% of Si. Maximum hardness of 30.3 ± 1.5 GPa was obtained at 4 at.% Si. The increase in the silicon content of Al-Si-N thin films promotes the formation of a-Si3 N4 matrix. Abstract: Al-Si-N thin films were deposited using simultaneous laser ablation of silicon and aluminum targets in a nitrogen atmosphere at a substrate temperature of 200 °C. The silicon content of the films was studied as a function of the plasma parameters (mean ion kinetic energy and plasma density), produced by the ablation of the silicon target. The plasma parameters were measured by means of a planar Langmuir probe and optical emission spectroscopy. The chemical composition of the films was determined by X-ray photoelectron spectroscopy. The results showed a dependence between the silicon content and the silicon plasma density. Optical emission spectroscopy measurements showed that variations of the working pressure produced changes in the intensity of excited species (N2 +, Si 2+, Al + and Al 0 ), and in the incorporation of these elements into the films. For a working pressure of 0.6 Pa, hardness measurements gave a maximum of 30 ± 1.5 GPa for a silicon content of 4 at.%. The optical constants (refractive index and extinction coefficient) and direct band gap were evaluated as a function of the silicon content in the films.