Evaluation of Mechanical Properties of Porous OSG Films by PFQNM AFM and Benchmarking with Traditional Instrumentation

Abstract

Characterization of mechanical properties of thin porous films with nanoscale resolution remains a challenge for instrumentation science. In this work, atomic force microscopy (AFM) in the PeakForce quantitative nanomechanical mapping (PFQNM) mode is used for Young's modulus measurements of porous organosilicate glass films. The test samples were prepared by sol−gel techniques using silicon alkoxide and methyl-modified silicon alkoxide to prepare films with different CH 3 /Si ratios. The film porosity was engineered by using a Brij 30 template and the evaporation-induced self-assembly technique. The chemical composition, pore structure, and modification during air storage and thermal annealing were studied using FTIR spectroscopy and ellipsometric porosimetry (EP). Since PFQNM AFM was first used for evaluation of Young's modulus of thin porous films, the obtained results are benchmarked using nanoindentation (NI), surface acoustic wave (SAW) spectroscopy, and EP. The results have good agreement with each other, but PFQNM and NI give slightly larger values than SAW and EP. The difference is in agreement with previously reported data and reflects the different physical meaning of the obtained values. It is shown that the presence of physically adsorbed water strongly influences the results generated by PFQNM AFM, and therefore, reliable water removal from the studied materials is necessary.

Design of Polyhydroxyalkanoate (PHA) Microbeads with Tunable Functional Properties and High Biodegradability in Seawater

“…Tip convolution effect is likely to occur, especially on rough surfaces as it is the case here and may result in different contact area which can affect the indentation modulus calculated from the force curve analysis. It has also been recently postulated that PFQNM experiments may provide slightly larger modulus as compared to other mechanical techniques, since the force curve may be partially impacted by the presence of adsorbed water that may increase the adhesion force between the tip and sample [70]. Nonetheless, the variation in the mechanical properties, as observed by the two techniques confirms that the bead present different mechanical properties, in correlation with their crystalline content and their chemical structure.…”

Damage to OSG low‐k films during IPVD deposition of the Ta barrier layer

“…Mechanical properties were determined by the methods described in Mogilnikov and colleagues. [40,41] The thickness of the film was 250 nm. The film had an open porosity of 40%, a pore radius of 1.7 nm, and Young's modulus of 2.8 GPa as measured by ellipsometric porosimetry.…”

Dielectric permittivity of organosilicate glass thin films on a sapphire substrate determined using time-domain THz and Fourier IR spectroscopy

“…The resonance lines in the range of 2800-2900 cm −1 are associated with vibrations of the hydrocarbon groups -CH 2 -and C-H 3 [7]. The spectrum of the p-OSG film contains a broad band in the range of 3000-3500 cm −1 , indicating the presence of a small amount of residual silanol functional groups Si-OH and water [29,53,54] trapped in isolated pores. This band was not observed in the spectrum of the p-OSG42 film because of the small number of isolated pores.…”