Modifications of Ti–6Al–4V surface roughness, wettability and composition are increasingly studied to improve cellular viability on biomedical implants involving Ti–6Al–4V. In this study, it is shown that modification of Ti–6Al–4V samples using anodization (for the formation of titania nanotubes) combined with thermal oxidation (TO) results in superior surface characteristics to those of a smooth, rough, anodized-smooth or anodized-rough surface alone. Surface characterization is performed using water contact angle (WCA) measurements, white-light interferometry, Fourier transform infrared spectroscopy (FTIRS), field emission scanning electron microscopy and grazing incidence X-ray diffraction (GIXRD). WCA measurements before TO indicate that anodized-smooth and anodized-rough samples are super-hydrophilic (WCA less than 5°); WCA of non-anodized smooth and rough surfaces are 57 ± 6° and 86 ± 7°, respectively. After TO at 450 °C for 3 hours, all samples become super-hydrophilic; however, three weeks after TO, smooth and rough surfaces become hydrophobic, while anodized-smooth and anodized-rough surfaces remain hydrophilic. FTIRS and GIXRD data show that the TO of anodized and non-anodized smooth samples results in anatase and rutile TiO₂, of which anatase is favorable for cellular attachment. Micro-/nano-scale roughness and TO are discussed in the context of enhanced Ti–6Al–4V surface characteristics for improved cellular response.

Atomic layer deposition (ALD) is a vapor-phase deposition technique that has attracted increasing attention from both experimentalists and theoreticians in the last few decades. ALD is well-known to produce conformal, uniform, and pinhole-free thin films across the surface of substrates. Due to these advantages, ALD has found many engineering and biomedical applications. However, drawbacks of ALD should be considered. For example, the reaction mechanisms cannot be thoroughly understood through experiments. Moreover, ALD conditions such as materials, pulse and purge durations, and temperature should be optimized for every experiment. It is practically impossible to perform many experiments to find materials and deposition conditions that achieve a thin film with desired applications. Additionally, only existing materials can be tested experimentally, which are often expensive and hazardous, and their use should be minimized. To overcome ALD limitations, theoretical methods are beneficial and essential complements to experimental data. Recently, theoretical approaches have been reported to model, predict, and optimize different ALD aspects, such as materials, mechanisms, and deposition characteristics. Those methods can be validated using a different theoretical approach or a few knowledge-based experiments. This review focuses on recent computational advances in thermal ALD and discusses how theoretical methods can make experiments more efficient.

A nonpyrophoric, oxygen-free, halogen-free tris(diethylamino) aluminum (TDEAA) precursor was used for atomic layer deposition (ALD) of aluminum oxide on <mml:math display="inline"><mml:mrow><mml:mi>Si</mml:mi><mml:mo>(</mml:mo><mml:mn>100</mml:mn><mml:mo>)</mml:mo></mml:mrow></mml:math>Si(100) . ALD of aluminum oxide using TDEAA and water was found to be self-limiting with respect to both reactants. The temperature window for ALD in the hotwall reactor used was found to be between 200 and <mml:math display="inline"><mml:mrow><mml:mn>400</mml:mn><mml:mo>°</mml:mo><mml:mi mathvariant="normal">C</mml:mi></mml:mrow></mml:math>400°C . The ALD rate was <mml:math display="inline"><mml:mrow><mml:mn>1.4</mml:mn><mml:mspace width="0.3em"></mml:mspace><mml:mi mathvariant="normal">Å</mml:mi><mml:mo>∕</mml:mo><mml:mi>cycle</mml:mi></mml:mrow></mml:math>1.4Å∕cycle at optimum conditions. Fourier transform infrared (FTIR) analyses indicated negligible interfacial <mml:math display="inline"><mml:mrow><mml:msub><mml:mi>SiO</mml:mi><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>SiO2 growth during deposition. Both FTIR spectra and transmission electron micrographs showed the ALD aluminum oxide to be amorphous. Also, FTIR and X-ray photoelectron spectral (XPS) analyses showed negligible carbon and nitrogen ( <mml:math display="inline"><mml:mrow><mml:mo><</mml:mo><mml:mn>1</mml:mn><mml:mo>%</mml:mo></mml:mrow></mml:math><1% atomic) contamination in the film. Z-contrast images and electron energy loss spectra showed uniform aluminum oxide film with an abrupt interface with Si. XPS analysis revealed aluminum oxide film to be stoichiometric with no detectable <mml:math display="inline"><mml:mrow><mml:mi>Al</mml:mi><mml:mo>–</mml:mo><mml:mi>Al</mml:mi></mml:mrow></mml:math>Al–Al cluster formation. Also, XP spectra showed no silicate formation at the interface of as-deposited alumina films.

Atomic layer deposited ultrathin and films were studied as diffusion barriers between Cu and Si substrate. The thermal stability of 3 nm thick and films was investigated after annealing at different temperatures for in . X-ray diffraction analyses and sheet resistance measurements suggest that both barrier films were thermally stable and the formation of started to take place only after annealing at high temperatures. Specifically, our results show that 3 nm thick and diffusion barriers break down after annealing in at 700 and , respectively.