Fabrication of amorphous Al₂O₃ optical film with various refractive index and low surface roughness

Abstract

Alumina(Al2O3) thin film has been widely used in many applications due to its excellent properties, especially in optical films and semiconductor industries. Refractive index, amorphous property and surface roughness are essential parameters related to its applications. In this study, the fabrication method of preparing various refractive index Al2O3 optical films was proposed. The Al2O3 optical films were deposited at room temperature by electron beam evaporation(EBE) technique. The effects of deposition rate and post-annealed temperature on refractive index, vibration peak of molecular and atom, amorphous property and surface roughness were investigated. Refractive index ranging from 1.519 to 1.627 was realized by EBE method at different deposition rates and different post-annealed temperatures. The variable refractive index was very important in adjusting half-width of reflector band. Meanwhile, analysis showed that the suitable post-annealed temperature could not exceed 400 °C. In short, this work provided an effective approach to fabricate amorphous Al2O3 optical film, which was pretty important in its applications in UV antireflection films and blue light reflection films.

Structure and optical properties of aluminum oxide films (Al2O3) after heating in water vapor and vacuum

“…Результаты расчетов показали, что показатель преломления n = 1,6-1,7 в интервале длин волн 400-1000 нм, а d = 300 нм. Полученное значение n оказалось близким к показателю преломления аморфных пленок оксида алюминия (n = 1,63) в работе [14]. Погрешность определения n и d определяли по сдвигу расчетной кривой пропускания относительно измеренной и составляла для показателя преломления около 0,02 и для d≤10 нм.…”

Use of plasma oxidation for conversion of metal salt infiltrated thin polymer films to metal oxide

“…The thickness variations observed in the AlO x layer could be attributed to formation of denser films for longer process times and for process conditions with stronger ion bombardment. Film density affects the optical constants of the film which would impact the thickness estimate [46].…”

Analysis of wide diffuse halo formation in the x-ray diffraction spectrum during the reduction of Fe2O3 by waste-activated sludge (WAS)

“…With the prevalence of amorphous oxide compounds, the main halo of amorphous Fe with a maximum intensity at 2θ∼45° [11,22] should be superimposed by a complex-shaped halo with maxima at 2θ∼23 °(main peak) and 2θ∼63 °(very weak peak) [23][24][25]. For amorphous carbon, the main and weaker peaks are found at 25°and 45°, respectively [19,20,26].…”