Comparative study of ALD SiO_2 thin films for optical applications

Abstract

Abstract:We have investigated the suitability of atomic layer deposition (ALD) for SiO 2 optical coatings and applied it to broadband antireflective multilayers in combination with HfO 2 as the high refractive index material. SiO 2 thin films were successfully grown using tris [dimethylamino]silane (3DMAS), bis [diethylamino]silane (BDEAS) with plasma activated oxygen as precursors, and the AP-LTO 330 precursor with ozone, respectively. The amorphous SiO 2 films show very low optical losses within a spectral range of 200 nm to 1100 nm. Laser calorimetric measurements show absorption losses of 300 nm thick SiO 2 films of about 1.5 parts per million at a wavelength of 1064 nm. The films are optically homogeneous and possess a good scalability of film thickness. The film surface porosity -which correlates to a shift in the transmittance spectra under vacuum and air conditions -has been suppressed by optimized plasma parameters or Al 2 O 3 sealing layers. and TiO 2 multilayers for applications as bandpass filters and antireflection coatings," Appl. Opt. 48(9), 1727-1732 (2009). 7. N. T. Gabriel, S. S. Kim, and J. J. Talghader, "Control of thermal deformation in dielectric mirrors using mechanical design and atomic layer deposition," Opt. Lett. 34(13), 1958-1960 (2009 4675-4685 (2012). 25. K. J. Hughes and J. R. Engstrom, "Nucleation delay in atomic layer deposition on a thin organic layer and the role of reaction thermochemistry," J.

Antireflection Coatings for Strongly Curved Glass Lenses by Atomic Layer Deposition

“…Al 2 O 3 has been applied in ALD antireflection coatings in combination with TiO 2 [17,20] or Ta 2 O 5 [28]. Next to this, SiO 2 is a very important low-index material that we recently applied in ALD optical coatings [19,21,28,29]. The properties of the single-layer films resulting from the ALD processes used in this work are summarized in Table 2.…”

“…We have previously shown a broadband AR coating on flat high refractive Atomic layer deposition (ALD) is an alternative and promising technology for uniform multilayer optical coatings [14][15][16][17][18]. We have previously shown a broadband AR coating on flat high refractive index glasses using SiO2/HfO2 multilayers [19]. Atomic layer deposition is also being considered for more complex interference coatings such as dichroic mirrors and narrow bandpass filters [16,20,21].…”

Atomic Layer Deposition for Coating of Complex 3D Optics

“…A raw comparison of ALD made films with ion beam sputtering (IBS) deposited materials shows that they are not absolutely identical, but can easily be implemented into optical designs. In addition, good film purity, very low level of absorption and a particle free growth make ALD a very promising method for challenging optical applications [6]. Further upscaling to multilayer stack coating designs can be done on planar or 3D optics with respect to suitable deposition parameters and reactor designs.…”

On the Properties of Nanoporous SiO2 Films for Single Layer Antireflection Coating

“…Light reflections, occurring at interfaces between materials and air due to the abrupt change of refractive indices must be eliminated in advanced optical components . Single layer antireflection coatings and gradient index antireflection (GIAR) coatings are preferred for numerous applications such as high power laser optical systems .…”