In Situ Study of Titanium Film Growth On Different Substrates

2000 ◽  
Vol 648 ◽  
Author(s):  
P. Oberhauser ◽  
M. Poppeller ◽  
R. Abermann
Keyword(s):  
Surface Roughness ◽  
Tensile Stress ◽  
Film Thickness ◽  
Film Growth ◽  
Substrate Surface ◽  
Growth Stress ◽  
Microstructural Properties ◽  
Titanium Film ◽  
High Degree

AbstractThe chemical and microstructural properties of a surface have a strong influence on the growth mode and the morphology of a film evaporated onto this interface. Changes in the growth stress of thin titanium films, measured in situ by a cantilever beam technique, evaporated under UHV-conditions are used to monitor the chemical and microstructural properties of a substrate surface. The starting substrate film used in this study was a quasi single-crystalline TiO2-film (d=50 nm) prepared by reactive evaporation of titanium in an oxygen atmosphere and subsequent annealing (20 min, 400°C). The Ti-growth stress on this substrate is compressive up to monolayer coverage and tensile at higher film thickness, which is interpreted to indicate a strong interaction between TiO2 and the arriving Ti atoms at the interface during monolayer formation and strained (tensile) layer epitaxy at higher film thickness. In a second series of experiments the TiO2-film was covered with Al-overlayers of varying thickness. Due to oxygen interdiffusion from the TiO2-film an amorphous Al-oxide layer is formed at the interface eliminating the high degree of order of the substrate TiO2-film. On this amorphous substrate the stress vs. thickness curve of the Ti-film, in terms of our stress model, is interpreted to indicate island formation and growth of a polycrystalline Ti-film. At Al-layer thicknesses above about 3 nm the Al-interface becomes metallic. The structure of this Al-surface depends on the film thickness and substrate temperature during its deposition. During deposition of the first Ti-monolayer on metallic Al a large incremental tensile stress (up to 45 GPa) is measured. The magnitude of this tensile stress is closely related to the surface microstructure of the Al substrate. The surface roughness deduced from the tensile interface stress is compared with the surface roughness measured by AFM.For comparison, analogous experiments were made with Al2O3/Al substrate bilayers. The results of these experiments qualitatively agree with those on the TiO2/Al-substrate. The general shape of the stress vs. thickness curve is comparable, however quantitative differences are interpreted to be due to differences in the structure and/or chemical composition of the substrate Al-film.

Underlayer Effects on the Growth Stress of Titanium Films

1994 ◽  
Vol 356 ◽  
Author(s):  
M. Poppeller ◽  
R. Abermann
Keyword(s):  
Water Content ◽  
Substrate Surface ◽  
Growth Stress ◽  
Base Layer ◽  
Titanium Film ◽  
Titanium Layer ◽  
Substrate Layer ◽  
Beam Technique ◽  
Substrate Film

AbstractThe growth stress of titanium films was measured in situ with a cantilever beam technique under UHV conditions at Ts ≥ 130°C. The substrate used in these experiments was a double layer consisting of a base layer of A12O3 or of MgF2 and as a second layer a titanium film evaporated at different H2O-partiaI pressures (Ti/TiOx). With both base layers the growth stress of the substrate Ti/TiOx layer is similar.The main objective of this paper was the investigation of the effect of a variation in the chemical composition of the substrate Ti/TiOx layer on the growth stress and -by way of our stress model - on the growth mode of a clean titanium film always evaporated under identical vacuum conditions onto this bilayered substrate. At low water content of the substrate titanium layer (the substrate layer still consists of metallic titanium) the growth of the clean titanium film is a continuation of the growth of the second substrate layer. As soon as the substrate titanium film contains only a few percent of water the initial compressive stress is overcompensated by atensile stress contribution which increases as the water content of the substrate isincreased. We interprete this to indicate renewed nucleation for the clean titanium film on the substrate surface. A small part of the tensile stress is also due to gas interdiffusion (hydrogen) from the substrate film. This effect is rather small when the second substrate film consists of stoichiometric oxide. With a MgF2 base layer in the substrate bilayer the results indicate a diffusing species from the MgF2 base layer into the Ti/TiOx layer. This interdiffusion from the substrate significantly affects the growth stress of the clean titanium film on this substrate bilayer. However, the general trends due to the incorporation of water in the substrate Ti/TiOx film, seen in case of the A12O3 base layer, are the same.

Effects of Substrate Properties, Film Thickness and Evaporation Rate on the Surface Roughness of Ultra Thin Titanium Films

2007 ◽  
Author(s):  
Guoqiang Han ◽  
Zhuangde Jiang ◽  
Weixuan Jing ◽  
Mingzhi Zhu
Keyword(s):  
Surface Roughness ◽  
Film Thickness ◽  
Surface Properties ◽  
Evaporation Rate ◽  
Substrate Surface ◽  
Film Surface ◽  
Deposition Process ◽  
Electron Beam Evaporation ◽  
Titanium Film ◽  
Substrate Surfaces

Ultra thin (less than 50nm) titanium films with various thicknesses are systematically deposited on different substrates by electron-beam evaporation at various deposition rates in order to correlate flat titanium film surface roughness with deposition process parameters. In this paper, the influences of the substrate surface properties, film thickness and evaporation rate on surface roughness of flat ultra thin titanium films are clarified. In this study, distinct and abrupt steps on the film surface were fabricated by masks pasted on the substrate surfaces during the deposition process. The step can be scanned with stylus profilometer to reveal the height of the step (the thickness of the thin film). Ultra thin films with height 20–50 nm were routinely measured in this way. It is important to notice that ultra thin titanium films with different surface roughness but having the same film thickness can be obtained in a controllable way. Therefore, the control of substrate surface roughness, film thickness and evaporation process is essential to prepare ultra thin titanium films with desired surface properties in reproducible way for further biological and nanostructure investigations of these materials.

Laser-Reflectance Interferometry Measurements of Diamond-Film Growth

MRS Bulletin ◽  
1995 ◽  
Vol 20 (5) ◽  
pp. 29-31 ◽  
Author(s):  
Christopher D. Zuiker ◽  
Dieter M. Gruen ◽  
Alan R. Krauss
Keyword(s):  
Film Thickness ◽  
Film Growth ◽  
Substrate Surface ◽  
Diamond Films ◽  
Thin Film Deposition ◽  
Film Deposition ◽  
Index Of Refraction ◽  
Ex Situ ◽  
Laser Reflectance

The remarkable properties of diamond, including its hardness, chemical inertness, high thermal conductivity, low coefficient of friction, optical transparency, and semiconducting properties, have led to considerable research in the area of diamond thin-film deposition. Diamond films have been characterized ex situ by a large number of diagnostic techniques including Raman spectroscopy, x-ray diffraction, SEM, and TEM. In situ diagnostics, which can provide information in real time as the film is growing, are less common.Laser-reflectance interferometry (LRI) has been used to monitor the growth of diamond films in situ. The technique involves measuring the intensity of a laser beam reflected from the substrate surface on which the film is growing. The reflected beam is the sum of beams reflected by the gas-diamond interface and the diamond-silicon interface. Oscillations in the reflectivity are observed as the film grows because of interference between the reflected beams. Each oscillation indicates an increase in film thickness of λ/2n, where λ is the laser wavelength and n is the index of refraction of the film. If the index of refraction of the film is known, the thickness and growth rate can be determined in situ. For LRI measurements with 632.8-nm-wavelength HeNe lasers, the index of refraction of diamond films has been found to be within 10% of the bulk diamond value of 2.4. Each oscillation therefore indicates an increase in film thickness of 0.13 μm.The reflectivity measured by LRI is also affected by scattering because of surface roughness.

In Situ Diagnostics of Vuv Laser Cvd of Semiconductor Interfaces by Ftir Spectroscopy and Spectroscopic Ellipsometry

1995 ◽  
Vol 397 ◽  
Author(s):  
M. Barth ◽  
J. Knobloch ◽  
P. Hess
Keyword(s):  
Film Thickness ◽  
Bulk Material ◽  
Substrate Surface ◽  
Cluster Formation ◽  
Interface Layer ◽  
Native Oxide ◽  
Initial Growth ◽  
Difference Spectra ◽  
Si Substrates

ABSTRACTThe growth of high quality amorphous hydrogenated semiconductor films was explored with different in situ spectroscopic methods. Nucleation of ArF laser-induced CVD of a-Ge:H on different substrates was investigated by real time ellipsometry, whereas the F2 laser (157nm) deposition of a-Si:H was monitored by FTIR transmission spectroscopy. The ellipsometric studies reveal a significant influence of the substrate surface on the nucleation stage, which in fact determines the electronic and mechanical properties of the bulk material. Coalescence of initial clusters occurs at a thickness of 16 Å for atomically smooth hydrogen-terminated c-Si substrates, whereas on native oxide covered c-Si substrates the bulk volume void fractions are not reached until 35 Å film thickness. For the first time we present a series of IR transmission spectra with monolayer resolution of the initial growth of a-Si:H. Hereby the film thickness was measured simultaneously using a quartz crystal microbalance with corresponding sensitivity. The results give evidence for cluster formation with a coalescence radius of about 20 Å. Difference spectra calculated for layers at different depths with definite thickness reveal that the hydrogen-rich interface layer stays at the substrate surface and does not move with the surface of the growing film. The decrease of the Urbach energy switching from native oxide to H-terminated substrates suggests a strong influence of the interface morphology on the bulk material quality.

Surface Properties and Cell Response of Bioactive Thermally Grown TiO2 Nanofibers

2014 ◽  
Vol 575 ◽  
pp. 219-222
Author(s):  
A.W. Tan ◽  
Belinda Pingguan-Murphy ◽  
Roslina Ahmad ◽  
Sheikh Akbar
Keyword(s):  
Surface Roughness ◽  
Articular Chondrocytes ◽  
Substrate Surface ◽  
Control Sample ◽  
Degree Of Crystallinity ◽  
Crystallographic Structure ◽  
Cartilage Growth ◽  
Bovine Articular Chondrocytes

Titania nanofiber (TiO2 NFs) arrays were fabricated in situ on a Ti-6Al-4V substrate by an oxidation process. Their surface morphology, crystallographic structure, surface roughness and wettability were characterized, as well as their in vitro interaction with bovine articular chondrocytes at different time points. Results showed that TiO2 NFs possessed greater surface roughness, hydrophilicity and degree of crystallinity. The in vitro cell studies revealed that TiO2 NFs substrate triggers enhanced cell adhesion, proliferation and extracellular matrix (ECM) formation compared to the untreated control sample. These results showed that chondrocytes have an affinity to the nanofibrous substrate surface and thus we suggest that such surfaces are suited to be used as an implant designed for cartilage growth.

Chemical vapour deposition tungsten film growth studied by in situ growth stress measurements

1993 ◽  
Vol 228 (1-2) ◽  
pp. 125-128 ◽  
Author(s):  
G.J. Leusink ◽  
T.G.M. Oosterlaken ◽  
G.C.A.M. Janssen ◽  
S. Redelaar
Keyword(s):  
Chemical Vapour Deposition ◽  
Vapour Deposition ◽  
Film Growth ◽  
Chemical Vapour ◽  
Growth Stress ◽  
In Situ Growth ◽  
Stress Measurements ◽  
Tungsten Film

scholarly journals The impact of film thickness and substrate surface roughness on the thermal resistance of aluminum nitride nucleation layers

2013 ◽  
Vol 113 (21) ◽  
pp. 213502 ◽  
Author(s):  
Zonghui Su ◽  
Justin P. Freedman ◽  
Jacob H. Leach ◽  
Edward A. Preble ◽  
Robert F. Davis ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Aluminum Nitride ◽  
Film Thickness ◽  
Thermal Resistance ◽  
Substrate Surface ◽  
Substrate Surface Roughness ◽  
The Impact

Regulation of film thickness, surface roughness and porosity in thin film growth using deposition rate

2009 ◽  
Vol 64 (17) ◽  
pp. 3903-3913 ◽  
Author(s):  
Gangshi Hu ◽  
Gerassimos Orkoulas ◽  
Panagiotis D. Christofides
Keyword(s):  
Thin Film ◽  
Surface Roughness ◽  
Film Thickness ◽  
Deposition Rate ◽  
Film Growth ◽  
Thin Film Growth

Continuous-Film Thickness Determination by AES of Cr Overlayers on Cu Surfaces

1989 ◽  
Vol 153 ◽  
Author(s):  
H. Lefakis ◽  
P.S. Ho
Keyword(s):  
Film Thickness ◽  
Rough Surface ◽  
Film Growth ◽  
Substrate Surface ◽  
Continuous Film ◽  
Substrate Heating ◽  
Native Oxides ◽  
Surface Oxides ◽  
Coverage Rates ◽  
Cr Film

AbstractThe characteristics of Cr coverage of Cu surfaces, including determination of tc, the minimum average film thickness required for formation of a continuous film, have been studied in-situ by Auger Electron Spectroscopy (AES). Auger signal intensities of substrate and deposit were monitored during Cr film growth by vapor deposition in UHV. It was shown that substrate surface morphology (roughness) has a dominant effect on coverage rate and tc. Slower coverage rates and larger tc′s were effected by the presence of native oxides, substrate heating (to 330°C) and H2O-vapor rich (5×10−5 Torr) ambient during Cr deposition. Surface oxides seemed to affect more the coverage of a smooth than a rough surface. Conversely, substrate heating affected more the coverage of a rough surface. The combined effect of substrate heating and water vapor rich atmosphere was pronounced for both smooth and rough surface coverages. Some of the main factors controlling these effects are discussed.

Chemical Properties of A-Si:H Interface Layers on Oxide-Covered and Hydrogen-Terminated Silicon

1996 ◽  
Vol 420 ◽  
Author(s):  
Jürgen Knobloch ◽  
Peter Hess
Keyword(s):  
Film Growth ◽  
Substrate Surface ◽  
Chemical Properties ◽  
Deposition Process ◽  
Native Oxide ◽  
Difference Spectra ◽  
Initial Stage ◽  
Laser Cvd ◽  
Interface Layers

AbstractHigh quality a-Si:H films were deposited by pulsed VUV (157nm) laser CVD, allowing digital control of the deposition process. Nucleation and growth on native oxide-covered Si (100) and on H-terminated Si (111) surfaces were studied in situ by FTIR transmission spectroscopy with sub-monolayer sensitivity. The film thickness was monitored simultaneously using a quartz crystal microbalance (QCM) with comparable resolution. The in situ spectra reveal that the nature of the substrate surface significantly influences the hydrogen bonding configuration in the interface region. In both cases the assumed cluster growth during the initial stage is characterized by a band around 2100cm−1, which is assigned to SiHX (x = 1 – 3) surface modes. This band broadens until the clusters coalesce and band saturation occurs. At this time a second band starts to grow at 2000cm−1, which is attributed to bulk SiH bonds. Difference spectra calculated for layers at different depths with definite thickness and the deconvolution of the broad feature observed during the very first stage of film growth indicate the existence of a hydrogen-rich layer at the substrate surface whose composition and thickness depend on the properties of the substrate surface.

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