Structural and Optical Properties of Aluminum Nitride Thin Films Deposited by Pulsed DC Magnetron Sputtering

Abstract

Aluminum nitride thin films were deposited on Si (100) substrate by pulsed DC (asymmetric bipolar) reactive magnetron sputtering under variable nitrogen flow in a gas mixture of argon and nitrogen. The deposited film was characterized by grazing incidence X-ray diffraction (GIXRD), atomic force microscope (AFM), spectroscopic ellipsometry, and secondary ion mass spectroscopy (SIMS). GIXRD results have shown (100) reflection of wurtzite AlN, whereas AFM micrographs have revealed very fine grained microstructure with average roughness in the range 6-8 nm. Spectroscopic ellipsometry measurements have indicated the band gap and refractive index of the film in the range 5.0-5.48 eV and 1.58-1.84, respectively. SIMS measurement has indicated the presence of oxygen in the film.

Role of oxygen contaminant on the physical properties of sputtered AlN thin films

“…Even though the bandgap values of the different films are very close each other, a trend with oxygen contamination is evidenced: the energy gap values follow the same behavior of the oxygen contamination, since an increase of oxygen content in aluminum nitride and oxynitride induces a widening of the energy gap [28,29]. For all samples, energy gap values are lower than crystalline AlN material [30,31]. The lowering of the band gap, observed as optical absorption below the fundamental edge, is induced by an exponential distribution of the density of localized states in the tails of the allowed bands.…”

Characteristic of Highperformance on Mild Steel/Aln Cermet Selective Surfaces Deposited by Rf Magnetron Sputtering

“…The polished substrate was once cleaned in a proprietary alkaline solution for 10 minutes at 75 ° C and then immersed in 15% HCl for 2 minutes at room temperature, which can be established by way of weighing the substrate earlier than and after the ion cleaning step. Before the authentic deposition, the aluminium goal is pre-sputtered in argon for about 10 to 15 minutes in order to eliminate the thin oxide layer on the surface [3][4]. During the pre-sputtering process, a manually operated closure is positioned between the magnetron cathode and the substrate.…”

Morphological features in aluminum nitride epilayers prepared by magnetron sputtering

“…There are a lot of methods for thin films fabrication, such as pulsed laser deposition, reactive molecular beam epitaxy, vacuum arc/cathodic arc deposition, DC/RF reactive sputtering, ion beam sputtering, metal-organic chemical vapor deposition etc. [26].…”

“…The studies of AlN thin film could be divided into the investigations which emphasize chemical and physical properties (mechanical, electrical, magnetic) [6,9,17,21,22], analysis of the films structure [4,7,12,15,16,19,[23][24][25]32] and combined, showing the dependences of the properties on the films morphology [2,11,13,14,26,[33][34][35]. The structure of the thin films can utterly differ from the structure of bulk material and have different structural perfection.…”