AVS 66th International Symposium & Exhibition
    Thin Films Division Tuesday Sessions
       Session TF+AP-TuM

Paper TF+AP-TuM13
ALD on Thermally and Chemically Treated Fused Silica and Glass Surfaces

Tuesday, October 22, 2019, 12:00 pm, Room A124-125

Session: ALD and CVD: Precursors and Process Development
Presenter: Tahereh Gholian Avval, Brigham Young University
Authors: T.G. Avval, Brigham Young University
G. Hodges, Brigham Young University
V. Carver, Brigham Young University
M.R. Linford, Brigham Young University
Correspondent: Click to Email
Silanol (SiOH) and surface hydroxyl (OH) groups strongly affect the absorption behavior of species onto silica (SiO2) surfaces. The density of hydroxyl (OH) groups on these surfaces are important for initiating and producing conformal thin films by atomic layer deposition (ALD). The combination of chemical and thermal treatments of surfaces in ALD increases insight into their chemistry. Different chemical treatments, including cleaning solutions of industrial importance, affect surface silanol density and consequently subsequent thin film growth by ALD. In this work, we describe the density of hydroxyl (OH) groups on fused silica surfaces and their effect on ALD. In particular, we hydroxylated pieces of fused silica with hydrofluoric acid (HF) and then heat treated it at 200, 500, 700 and 900 °C. The samples then underwent different numbers of ALD cycles to produce thin films of Al2O3. As expected, analysis of these surfaces by X-ray photoelectron spectroscopy (XPS) showed that higher temperatures lead to lower aluminum loading/deposition. As a result, heat-treated samples at 900 °C appear to be significantly depleted in surface silanols and lagged behind in thickness compared to the other samples. Other chemical treatments of industrial relevance for silica and glass were also considered in this study, including hydrochloric acid (HCl), tetramethylammonium hydroxide (TMAH), and a detergent. This information is important for ALD deposition of this important material.